From 3e6f9f91b4151971953927d1ea3f50a5295def27 Mon Sep 17 00:00:00 2001
From: Vamshi Surabhi <vamshi@hasura.io>
Date: Wed, 15 Apr 2020 15:04:24 +0530
Subject: [PATCH 01/29] [skip ci] generate relay schema

---
 .../src-lib/Hasura/GraphQL/Resolve/Types.hs   |   2 +
 server/src-lib/Hasura/GraphQL/Schema.hs       |  21 +++-
 .../src-lib/Hasura/GraphQL/Schema/Common.hs   |   8 ++
 .../src-lib/Hasura/GraphQL/Schema/Function.hs |  17 +++
 .../src-lib/Hasura/GraphQL/Schema/Select.hs   | 104 +++++++++++++++++-
 5 files changed, 146 insertions(+), 6 deletions(-)

diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Types.hs b/server/src-lib/Hasura/GraphQL/Resolve/Types.hs
index d8fdcbd067f5e..3dda96769d2ed 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Types.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Types.hs
@@ -29,10 +29,12 @@ import qualified Hasura.SQL.DML                 as S
 
 data QueryCtx
   = QCSelect !SelOpCtx
+  | QCSelectConnection !SelOpCtx
   | QCSelectPkey !SelPkOpCtx
   | QCSelectAgg !SelOpCtx
   | QCFuncQuery !FuncQOpCtx
   | QCFuncAggQuery !FuncQOpCtx
+  | QCFuncConnection !FuncQOpCtx
   | QCActionFetch !ActionSelectOpContext
   deriving (Show, Eq)
 
diff --git a/server/src-lib/Hasura/GraphQL/Schema.hs b/server/src-lib/Hasura/GraphQL/Schema.hs
index 151e5602d8c13..0126f01838fb6 100644
--- a/server/src-lib/Hasura/GraphQL/Schema.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema.hs
@@ -154,10 +154,10 @@ mkGCtxRole' tn descM insPermM selPermM updColsM delPermM pkeyCols constraints vi
                <> queryTypes <> aggQueryTypes <> mutationTypes
                <> funcInpArgTys <> referencedEnumTypes <> computedFieldFuncArgsInps
 
-    queryTypes = catMaybes
+    queryTypes = map TIObj selectObjects <>
+      catMaybes
       [ TIInpObj <$> boolExpInpObjM
       , TIInpObj <$> ordByInpObjM
-      , TIObj <$> selObjM
       ]
     aggQueryTypes = map TIObj aggObjs <> map TIInpObj aggOrdByInps
 
@@ -254,7 +254,13 @@ mkGCtxRole' tn descM insPermM selPermM updColsM delPermM pkeyCols constraints vi
             && any (`isMutable` viM) [viIsInsertable, viIsUpdatable, viIsDeletable]
 
     -- table obj
-    selObjM = mkTableObj tn descM <$> selFldsM
+    selectObjects = case selPermM of
+      Just (_, selFlds) ->
+        [ mkTableObj tn descM selFlds
+        , mkTableEdgeObj tn
+        , mkTableConnectionObj tn
+        ]
+      Nothing -> []
 
     -- aggregate objs and order by inputs
     (aggObjs, aggOrdByInps) = case selPermM of
@@ -339,9 +345,11 @@ getRootFldsRole' tn primaryKey constraints fields funcs insM
   RootFields
     { _rootQueryFields = makeFieldMap $
         funcQueries
+        <> funcConnectionQueries
         <> funcAggQueries
         <> catMaybes
           [ getSelDet <$> selM
+          , getSelConnectionDet <$> selM
           , getSelAggDet selM
           , getPKeySelDet <$> selM <*> primaryKey
           ]
@@ -360,6 +368,7 @@ getRootFldsRole' tn primaryKey constraints fields funcs insM
     colGNameMap = mkPGColGNameMap $ getCols fields
 
     funcQueries = maybe [] getFuncQueryFlds selM
+    funcConnectionQueries = maybe [] getFuncQueryConnectionFlds selM
     funcAggQueries = maybe [] getFuncAggQueryFlds selM
 
     mutHelper :: (ViewInfo -> Bool) -> (a -> b) -> Maybe a -> Maybe b
@@ -411,6 +420,8 @@ getRootFldsRole' tn primaryKey constraints fields funcs insM
     selCustName = getCustomNameWith _tcrfSelect
     getSelDet (selFltr, pLimit, hdrs, _) =
       selFldHelper QCSelect (mkSelFld selCustName) selFltr pLimit hdrs
+    getSelConnectionDet (selFltr, pLimit, hdrs, _) =
+      selFldHelper QCSelectConnection (mkSelFldConnection Nothing) selFltr pLimit hdrs
 
     selAggCustName = getCustomNameWith _tcrfSelectAggregate
     getSelAggDet (Just (selFltr, pLimit, hdrs, True)) =
@@ -433,6 +444,9 @@ getRootFldsRole' tn primaryKey constraints fields funcs insM
     getFuncQueryFlds (selFltr, pLimit, hdrs, _) =
       funcFldHelper QCFuncQuery mkFuncQueryFld selFltr pLimit hdrs
 
+    getFuncQueryConnectionFlds (selFltr, pLimit, hdrs, _) =
+      funcFldHelper QCFuncConnection mkFuncQueryConnectionFld selFltr pLimit hdrs
+
     getFuncAggQueryFlds (selFltr, pLimit, hdrs, True) =
       funcFldHelper QCFuncAggQuery mkFuncAggQueryFld selFltr pLimit hdrs
     getFuncAggQueryFlds _                             = []
@@ -802,6 +816,7 @@ mkGCtx tyAgg (RootFields queryFields mutationFields) insCtxMap =
                             , TIObj <$> mutRootM
                             , TIObj <$> subRootM
                             , TIEnum <$> ordByEnumTyM
+                            , Just $ TIObj mkPageInfoObj
                             ] <>
                   scalarTys <> compTys <> defaultTypes <> wiredInGeoInputTypes
                   <> wiredInRastInputTypes
diff --git a/server/src-lib/Hasura/GraphQL/Schema/Common.hs b/server/src-lib/Hasura/GraphQL/Schema/Common.hs
index 31dcab5f16c68..bf3ede49f1ce6 100644
--- a/server/src-lib/Hasura/GraphQL/Schema/Common.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/Common.hs
@@ -16,6 +16,8 @@ module Hasura.GraphQL.Schema.Common
   , mkComputedFieldName
 
   , mkTableTy
+  , mkTableConnectionTy
+  , mkTableEdgeTy
   , mkTableEnumType
   , mkTableAggTy
 
@@ -91,6 +93,12 @@ mkColumnType = \case
 mkTableTy :: QualifiedTable -> G.NamedType
 mkTableTy = G.NamedType . qualObjectToName
 
+mkTableConnectionTy :: QualifiedTable -> G.NamedType
+mkTableConnectionTy = addTypeSuffix "Connection" . mkTableTy
+
+mkTableEdgeTy :: QualifiedTable -> G.NamedType
+mkTableEdgeTy = addTypeSuffix "Edge" . mkTableTy
+
 mkTableEnumType :: QualifiedTable -> G.NamedType
 mkTableEnumType = addTypeSuffix "_enum" . mkTableTy
 
diff --git a/server/src-lib/Hasura/GraphQL/Schema/Function.hs b/server/src-lib/Hasura/GraphQL/Schema/Function.hs
index f3349635069e6..79b4212eb509b 100644
--- a/server/src-lib/Hasura/GraphQL/Schema/Function.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/Function.hs
@@ -2,6 +2,7 @@ module Hasura.GraphQL.Schema.Function
   ( procFuncArgs
   , mkFuncArgsInp
   , mkFuncQueryFld
+  , mkFuncQueryConnectionFld
   , mkFuncAggQueryFld
   , mkFuncArgsTy
   ) where
@@ -92,6 +93,20 @@ mkFuncQueryFld funInfo descM =
 
     ty      = G.toGT $ G.toNT $ G.toLT $ G.toNT $ mkTableTy retTable
 
+mkFuncQueryConnectionFld
+  :: FunctionInfo -> Maybe PGDescription -> ObjFldInfo
+mkFuncQueryConnectionFld funInfo descM =
+  mkHsraObjFldInfo (Just desc) fldName (mkFuncArgs funInfo) ty
+  where
+    retTable = fiReturnType funInfo
+    funcName = fiName funInfo
+
+    desc = mkDescriptionWith descM $ "execute function " <> funcName
+           <<> " which returns " <>> retTable
+    fldName = qualObjectToName funcName <> "_connection"
+
+    ty = G.toGT $ G.toNT $ G.toLT $ G.toNT $ mkTableConnectionTy retTable
+
 {-
 
 function_aggregate(
@@ -118,3 +133,5 @@ mkFuncAggQueryFld funInfo descM =
     fldName = qualObjectToName funcName <> "_aggregate"
 
     ty = G.toGT $ G.toNT $ mkTableAggTy retTable
+
+
diff --git a/server/src-lib/Hasura/GraphQL/Schema/Select.hs b/server/src-lib/Hasura/GraphQL/Schema/Select.hs
index a3179466a53ec..1ded33b5cd429 100644
--- a/server/src-lib/Hasura/GraphQL/Schema/Select.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/Select.hs
@@ -4,10 +4,15 @@ module Hasura.GraphQL.Schema.Select
   , mkSelColumnTy
   , mkTableAggFldsObj
   , mkTableColAggFldsObj
+  , mkTableEdgeObj
+  , mkPageInfoObj
+  , mkTableConnectionObj
+  , mkTableConnectionTy
 
   , mkSelFld
   , mkAggSelFld
   , mkSelFldPKey
+  , mkSelFldConnection
 
   , mkSelArgs
   ) where
@@ -138,7 +143,7 @@ mkRelationshipField
   -> Bool
   -> [ObjFldInfo]
 mkRelationshipField allowAgg (RelInfo rn rTy _ remTab isManual) isNullable = case rTy of
-  ArrRel -> bool [arrRelFld] [arrRelFld, aggArrRelFld] allowAgg
+  ArrRel -> bool [arrRelFld] [arrRelFld, arrConnectionFld, aggArrRelFld] allowAgg
   ObjRel -> [objRelFld]
   where
     objRelFld = mkHsraObjFldInfo (Just "An object relationship")
@@ -149,8 +154,14 @@ mkRelationshipField allowAgg (RelInfo rn rTy _ remTab isManual) isNullable = cas
 
     arrRelFld =
       mkHsraObjFldInfo (Just "An array relationship") (mkRelName rn)
-      (fromInpValL $ mkSelArgs remTab) arrRelTy
-    arrRelTy = G.toGT $ G.toNT $ G.toLT $ G.toNT $ mkTableTy remTab
+      (fromInpValL $ mkSelArgs remTab) $
+      G.toGT $ G.toNT $ G.toLT $ G.toNT $ mkTableTy remTab
+
+    arrConnectionFld =
+      mkHsraObjFldInfo Nothing (mkRelName rn <> "_connection")
+      (fromInpValL $ mkSelArgs remTab) $
+      G.toGT $ G.toNT $ G.toLT $ G.toNT $ mkTableConnectionTy remTab
+
     aggArrRelFld = mkHsraObjFldInfo (Just "An aggregated array relationship")
       (mkAggRelName rn) (fromInpValL $ mkSelArgs remTab) $
       G.toGT $ G.toNT $ mkTableAggTy remTab
@@ -280,6 +291,93 @@ mkSelFld mCustomName tn =
     args    = fromInpValL $ mkSelArgs tn
     ty      = G.toGT $ G.toNT $ G.toLT $ G.toNT $ mkTableTy tn
 
+{-
+
+table(
+  where: table_bool_exp
+  limit: Int
+  offset: Int
+):  [tableConnection!]!
+
+-}
+
+mkSelFldConnection :: Maybe G.Name -> QualifiedTable -> ObjFldInfo
+mkSelFldConnection mCustomName tn =
+  mkHsraObjFldInfo (Just desc) fldName args ty
+  where
+    desc    = G.Description $ "fetch data from the table: " <>> tn
+    fldName = fromMaybe (qualObjectToName tn <> "_connection") mCustomName
+    args    = fromInpValL $ mkSelArgs tn
+    ty      = G.toGT $ G.toNT $ G.toLT $ G.toNT $ mkTableConnectionTy tn
+
+{-
+type tableConnection {
+  pageInfo: PageInfo!
+  edges: [tableEdge!]!
+}
+-}
+mkTableConnectionObj
+  :: QualifiedTable -> ObjTyInfo
+mkTableConnectionObj tn =
+  mkHsraObjTyInfo (Just desc) (mkTableConnectionTy tn) Set.empty $ mapFromL _fiName
+  [pageInfoFld, edgesFld]
+  where
+    desc = G.Description $ "A Relay Connection object on " <>> tn
+    pageInfoFld = mkHsraObjFldInfo Nothing "pageInfo" Map.empty $
+                  G.toGT $ G.toNT $ pageInfoTy
+    edgesFld = mkHsraObjFldInfo Nothing "edges" Map.empty $ G.toGT $
+               G.toNT $ G.toLT $ G.toNT $ mkTableEdgeTy tn
+
+booleanScalar :: G.NamedType
+booleanScalar = G.NamedType "Boolean"
+
+stringScalar :: G.NamedType
+stringScalar = G.NamedType "String"
+
+pageInfoTyName :: G.Name
+pageInfoTyName = "PageInfo"
+
+pageInfoTy :: G.NamedType
+pageInfoTy = G.NamedType pageInfoTyName
+{-
+type PageInfo {
+  hasNextPage: Boolean!
+  hasPrevousPage: Boolean!
+  startCursor: String!
+  endCursor: String!
+}
+-}
+mkPageInfoObj :: ObjTyInfo
+mkPageInfoObj =
+  mkHsraObjTyInfo Nothing pageInfoTy Set.empty $ mapFromL _fiName
+  [hasNextPage, hasPreviousPage, startCursor, endCursor]
+  where
+    hasNextPage = mkHsraObjFldInfo Nothing "hasNextPage" Map.empty $
+                  G.toGT $ G.toNT booleanScalar
+    hasPreviousPage = mkHsraObjFldInfo Nothing "hasPreviousPage" Map.empty $
+                      G.toGT $ G.toNT booleanScalar
+    startCursor = mkHsraObjFldInfo Nothing "startCursor" Map.empty $
+                  G.toGT $ G.toNT stringScalar
+    endCursor = mkHsraObjFldInfo Nothing "endCursor" Map.empty $
+                G.toGT $ G.toNT stringScalar
+
+{-
+type tableConnection {
+  cursor: String!
+  node: table
+}
+-}
+mkTableEdgeObj
+  :: QualifiedTable -> ObjTyInfo
+mkTableEdgeObj tn =
+  mkHsraObjTyInfo Nothing (mkTableEdgeTy tn) Set.empty $ mapFromL _fiName
+  [cursor, node]
+  where
+    cursor = mkHsraObjFldInfo Nothing "cursor" Map.empty $
+             G.toGT $ G.toNT stringScalar
+    node = mkHsraObjFldInfo Nothing "node" Map.empty $ G.toGT $
+           mkTableTy tn
+
 {-
 table_by_pk(
   col1: value1!,

From 615fccb4156af3f901667ca3d51d3a79930eeef5 Mon Sep 17 00:00:00 2001
From: Vamshi Surabhi <vamshi@hasura.io>
Date: Fri, 17 Apr 2020 19:50:19 +0530
Subject: [PATCH 02/29] [skip ci] wip: query generation logic for Relay
 Connection spec

---
 server/src-lib/Hasura/GraphQL/Resolve.hs      |   7 +
 .../src-lib/Hasura/GraphQL/Resolve/Select.hs  | 115 +++++++++++++-
 .../src-lib/Hasura/GraphQL/Schema/Select.hs   |  30 +++-
 .../src-lib/Hasura/RQL/DML/Select/Internal.hs | 150 ++++++++++++++++++
 server/src-lib/Hasura/RQL/DML/Select/Types.hs |  79 +++++++--
 server/src-lib/Hasura/RQL/Types/BoolExp.hs    |   8 +
 server/src-lib/Hasura/RQL/Types/Column.hs     |   1 +
 server/src-lib/Hasura/RQL/Types/Common.hs     |   1 +
 server/src-lib/Hasura/RQL/Types/DML.hs        |   5 +-
 server/src-lib/Hasura/SQL/DML.hs              |  47 ++++--
 server/src-lib/Hasura/SQL/Types.hs            |   2 +-
 11 files changed, 417 insertions(+), 28 deletions(-)

diff --git a/server/src-lib/Hasura/GraphQL/Resolve.hs b/server/src-lib/Hasura/GraphQL/Resolve.hs
index f2dc4d766b20d..3e4b03357d4e9 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve.hs
@@ -44,6 +44,7 @@ data QueryRootFldAST v
   = QRFPk !(DS.AnnSimpleSelG v)
   | QRFSimple !(DS.AnnSimpleSelG v)
   | QRFAgg !(DS.AnnAggSelG v)
+  | QRFConnection !(DS.ConnectionSelect v)
   | QRFActionSelect !(DS.AnnSimpleSelG v)
   deriving (Show, Eq)
 
@@ -59,6 +60,7 @@ traverseQueryRootFldAST f = \case
   QRFPk s           -> QRFPk <$> DS.traverseAnnSimpleSel f s
   QRFSimple s       -> QRFSimple <$> DS.traverseAnnSimpleSel f s
   QRFAgg s          -> QRFAgg <$> DS.traverseAnnAggSel f s
+  QRFConnection s   -> QRFConnection <$> DS.traverseConnectionSelect f s
   QRFActionSelect s -> QRFActionSelect <$> DS.traverseAnnSimpleSel f s
 
 toPGQuery :: QueryRootFldResolved -> Q.Query
@@ -67,6 +69,7 @@ toPGQuery = \case
   QRFSimple s       -> DS.selectQuerySQL DS.JASMultipleRows s
   QRFAgg s          -> DS.selectAggQuerySQL s
   QRFActionSelect s -> DS.selectQuerySQL DS.JASSingleObject s
+  QRFConnection s   -> Q.fromBuilder $ toSQL $ DS.mkConnectionSelect s
 
 validateHdrs
   :: (Foldable t, QErrM m) => UserInfo -> t Text -> m ()
@@ -104,6 +107,10 @@ queryFldToPGAST fld = do
       QRFAgg <$> RS.convertFuncQueryAgg ctx fld
     QCActionFetch ctx ->
       QRFActionSelect <$> RA.resolveAsyncActionQuery userInfo ctx fld
+    QCSelectConnection ctx -> do
+      QRFConnection <$> RS.convertConnectionSelect ctx fld
+    QCFuncConnection ctx -> do
+      QRFConnection <$> RS.convertConnectionFuncQuery ctx fld
 
 mutFldToTx
   :: ( HasVersion
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Select.hs b/server/src-lib/Hasura/GraphQL/Resolve/Select.hs
index 704fc543f2eb5..5b9aaca18e0dc 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Select.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Select.hs
@@ -1,5 +1,7 @@
 module Hasura.GraphQL.Resolve.Select
   ( convertSelect
+  , convertConnectionSelect
+  , convertConnectionFuncQuery
   , convertSelectByPKey
   , convertAggSelect
   , convertFuncQuerySimple
@@ -130,6 +132,53 @@ fromAggSelSet colGNameMap fldTy selSet = fmap toFields $
       "nodes"      -> RS.TAFNodes <$> processTableSelectionSet fTy fSelSet
       G.Name t     -> throw500 $ "unexpected field in _agg node: " <> t
 
+fromConnectionSelSet
+  :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
+     , Has OrdByCtx r, Has SQLGenCtx r
+     )
+  => G.NamedType -> SelSet -> m (RS.ConnectionFields UnresolvedVal)
+fromConnectionSelSet fldTy selSet = fmap toFields $
+  withSelSet selSet $ \f -> do
+    let fTy = _fType f
+        fSelSet = _fSelSet f
+    case _fName f of
+      "__typename" -> return $ RS.ConnectionTypename $ G.unName $ G.unNamedType fldTy
+      "pageInfo"   -> RS.ConnectionPageInfo <$> parsePageInfoSelectionSet fTy fSelSet
+      "edges"      -> RS.ConnectionEdges <$> parseEdgeSelectionSet fTy fSelSet
+      -- "aggregate"  -> RS.TAFAgg <$> convertAggFld colGNameMap fTy fSelSet
+      -- "nodes"      -> RS.TAFNodes <$> processTableSelectionSet fTy fSelSet
+      G.Name t     -> throw500 $ "unexpected field in _connection node: " <> t
+
+parseEdgeSelectionSet
+  :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
+     , Has OrdByCtx r, Has SQLGenCtx r
+     )
+  => G.NamedType -> SelSet -> m (RS.EdgeFields UnresolvedVal)
+parseEdgeSelectionSet fldTy selSet = fmap toFields $
+  withSelSet selSet $ \f -> do
+    let fTy = _fType f
+        fSelSet = _fSelSet f
+    case _fName f of
+      "__typename" -> pure $ RS.EdgeTypename $ G.unName $ G.unNamedType fldTy
+      "cursor"     -> pure $ RS.EdgeCursor
+      "node"       -> RS.EdgeNode <$> processTableSelectionSet fTy fSelSet
+      G.Name t     -> throw500 $ "unexpected field in Edge node: " <> t
+
+parsePageInfoSelectionSet
+  :: ( MonadReusability m, MonadError QErr m)
+  => G.NamedType -> SelSet -> m RS.PageInfoFields
+parsePageInfoSelectionSet fldTy selSet =
+  fmap toFields $ withSelSet selSet $ \f ->
+    case _fName f of
+      "__typename"  -> pure $ RS.PageInfoTypename $ G.unName $ G.unNamedType fldTy
+      "hasNextPage" -> pure $ RS.PageInfoHasNextPage
+      "hasPreviousPage" -> pure $ RS.PageInfoHasPreviousPage
+      "startCursor" -> pure $ RS.PageInfoStartCursor
+      "endCursor" -> pure $ RS.PageInfoEndCursor
+      -- "aggregate"  -> RS.TAFAgg <$> convertAggFld colGNameMap fTy fSelSet
+      -- "nodes"      -> RS.TAFNodes <$> processTableSelectionSet fTy fSelSet
+      G.Name t     -> throw500 $ "unexpected field in PageInfo node: " <> t
+
 type TableArgs = RS.TableArgsG UnresolvedVal
 
 parseTableArgs
@@ -344,14 +393,18 @@ convertSelectByPKey opCtx fld =
     SelPkOpCtx qt _ permFilter colArgMap = opCtx
 
 -- agg select related
-parseColumns :: (MonadReusability m, MonadError QErr m) => PGColGNameMap -> AnnInpVal -> m [PGCol]
+parseColumns
+  :: (MonadReusability m, MonadError QErr m)
+  => PGColGNameMap -> AnnInpVal -> m [PGCol]
 parseColumns allColFldMap val =
   flip withArray val $ \_ vals ->
     forM vals $ \v -> do
       (_, G.EnumValue enumVal) <- asEnumVal v
       pgiColumn <$> resolvePGCol allColFldMap enumVal
 
-convertCount :: (MonadReusability m, MonadError QErr m) => PGColGNameMap -> ArgsMap -> m S.CountType
+convertCount
+  :: (MonadReusability m, MonadError QErr m)
+  => PGColGNameMap -> ArgsMap -> m S.CountType
 convertCount colGNameMap args = do
   columnsM <- withArgM args "columns" $ parseColumns colGNameMap
   isDistinct <- or <$> withArgM args "distinct" parseDistinct
@@ -419,6 +472,37 @@ fromAggField selectFrom colGNameMap permFilter permLimit fld = fieldAsPath fld $
   where
     args = _fArguments fld
 
+fromConnectionField
+  :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
+     , Has OrdByCtx r, Has SQLGenCtx r
+     )
+  => RS.SelectFromG UnresolvedVal
+  -> AnnBoolExpPartialSQL
+  -> Maybe Int
+  -> Field -> m (RS.ConnectionSelect UnresolvedVal)
+fromConnectionField selectFrom permFilter permLimit fld = fieldAsPath fld $ do
+  tableArgs   <- parseConnectionArgs args
+  aggSelFlds  <- fromConnectionSelSet (_fType fld) (_fSelSet fld)
+  let unresolvedPermFltr =
+        fmapAnnBoolExp partialSQLExpToUnresolvedVal permFilter
+  let tabPerm = RS.TablePerm unresolvedPermFltr permLimit
+  strfyNum <- stringifyNum <$> asks getter
+  return $ RS.AnnSelG aggSelFlds selectFrom tabPerm tableArgs strfyNum
+  where
+    args = _fArguments fld
+
+parseConnectionArgs
+  :: ( MonadReusability m, MonadError QErr m, MonadReader r m
+     , Has FieldMap r, Has OrdByCtx r
+     )
+  => ArgsMap -> m TableArgs
+parseConnectionArgs args = do
+  whereExpM  <- withArgM args "where" parseBoolExp
+  ordByExpML <- withArgM args "order_by" parseOrderBy
+  let ordByExpM = NE.nonEmpty =<< ordByExpML
+  -- limitExpM  <- withArgM args "limit" parseLimit
+  return $ RS.TableArgs whereExpM ordByExpM Nothing Nothing Nothing
+
 convertAggSelect
   :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
      , Has OrdByCtx r, Has SQLGenCtx r
@@ -430,6 +514,17 @@ convertAggSelect opCtx fld =
   where
     SelOpCtx qt _ colGNameMap permFilter permLimit = opCtx
 
+convertConnectionSelect
+  :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
+     , Has OrdByCtx r, Has SQLGenCtx r
+     )
+  => SelOpCtx -> Field -> m (RS.ConnectionSelect UnresolvedVal)
+convertConnectionSelect opCtx fld =
+  withPathK "selectionSet" $
+  fromConnectionField (RS.FromTable qt) permFilter permLimit fld
+  where
+    SelOpCtx qt _ _ permFilter permLimit = opCtx
+
 parseFunctionArgs
   :: (MonadReusability m, MonadError QErr m)
   => Seq.Seq a
@@ -512,3 +607,19 @@ convertFuncQueryAgg funcOpCtx fld =
     fromAggField selectFrom colGNameMap permFilter permLimit fld
   where
     FuncQOpCtx qf argSeq _ colGNameMap permFilter permLimit = funcOpCtx
+
+convertConnectionFuncQuery
+  :: ( MonadReusability m
+     , MonadError QErr m
+     , MonadReader r m
+     , Has FieldMap r
+     , Has OrdByCtx r
+     , Has SQLGenCtx r
+     )
+  => FuncQOpCtx -> Field -> m (RS.ConnectionSelect UnresolvedVal)
+convertConnectionFuncQuery funcOpCtx fld =
+  withPathK "selectionSet" $ fieldAsPath fld $ do
+    selectFrom <- makeFunctionSelectFrom qf argSeq fld
+    fromConnectionField selectFrom permFilter permLimit fld
+  where
+    FuncQOpCtx qf argSeq _ _ permFilter permLimit = funcOpCtx
diff --git a/server/src-lib/Hasura/GraphQL/Schema/Select.hs b/server/src-lib/Hasura/GraphQL/Schema/Select.hs
index 1ded33b5cd429..5ae4744e86d21 100644
--- a/server/src-lib/Hasura/GraphQL/Schema/Select.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/Select.hs
@@ -15,6 +15,7 @@ module Hasura.GraphQL.Schema.Select
   , mkSelFldConnection
 
   , mkSelArgs
+  , mkConnectionArgs
   ) where
 
 import qualified Data.HashMap.Strict           as Map
@@ -83,6 +84,7 @@ mkComputedFieldFld field =
       in (inputParams, G.toGT $ mkScalarTy scalarTy)
     CFTTable computedFieldtable ->
       let table = _cftTable computedFieldtable
+      -- TODO: connection stuff
       in ( fromInpValL $ maybeToList maybeFunctionInputArg <> mkSelArgs table
          , G.toGT $ G.toLT $ G.toNT $ mkTableTy table
          )
@@ -122,6 +124,30 @@ mkSelArgs tn =
     orderByDesc = "sort the rows by one or more columns"
     distinctDesc = "distinct select on columns"
 
+-- distinct_on: [table_select_column!]
+-- where: table_bool_exp
+-- order_by: table_order_by
+-- first: Int
+-- after: String
+-- last: Int
+-- before: String
+mkConnectionArgs :: QualifiedTable -> [InpValInfo]
+mkConnectionArgs tn =
+  [ InpValInfo (Just whereDesc) "where" Nothing $ G.toGT $ mkBoolExpTy tn
+  , InpValInfo (Just orderByDesc) "order_by" Nothing $ G.toGT $ G.toLT $ G.toNT $
+    mkOrdByTy tn
+  , InpValInfo (Just distinctDesc) "distinct_on" Nothing $ G.toGT $ G.toLT $
+    G.toNT $ mkSelColumnInpTy tn
+  , InpValInfo Nothing "first" Nothing $ G.toGT $ mkScalarTy PGInteger
+  , InpValInfo Nothing "after" Nothing $ G.toGT $ mkScalarTy PGText
+  , InpValInfo Nothing "last" Nothing $ G.toGT $ mkScalarTy PGInteger
+  , InpValInfo Nothing "before" Nothing $ G.toGT $ mkScalarTy PGText
+  ]
+  where
+    whereDesc   = "filter the rows returned"
+    orderByDesc = "sort the rows by one or more columns"
+    distinctDesc = "distinct select on columns"
+
 {-
 
 array_relationship(
@@ -159,7 +185,7 @@ mkRelationshipField allowAgg (RelInfo rn rTy _ remTab isManual) isNullable = cas
 
     arrConnectionFld =
       mkHsraObjFldInfo Nothing (mkRelName rn <> "_connection")
-      (fromInpValL $ mkSelArgs remTab) $
+      (fromInpValL $ mkConnectionArgs remTab) $
       G.toGT $ G.toNT $ G.toLT $ G.toNT $ mkTableConnectionTy remTab
 
     aggArrRelFld = mkHsraObjFldInfo (Just "An aggregated array relationship")
@@ -307,7 +333,7 @@ mkSelFldConnection mCustomName tn =
   where
     desc    = G.Description $ "fetch data from the table: " <>> tn
     fldName = fromMaybe (qualObjectToName tn <> "_connection") mCustomName
-    args    = fromInpValL $ mkSelArgs tn
+    args    = fromInpValL $ mkConnectionArgs tn
     ty      = G.toGT $ G.toNT $ G.toLT $ G.toNT $ mkTableConnectionTy tn
 
 {-
diff --git a/server/src-lib/Hasura/RQL/DML/Select/Internal.hs b/server/src-lib/Hasura/RQL/DML/Select/Internal.hs
index c6cd5b60121c0..360c5a4245108 100644
--- a/server/src-lib/Hasura/RQL/DML/Select/Internal.hs
+++ b/server/src-lib/Hasura/RQL/DML/Select/Internal.hs
@@ -1,6 +1,8 @@
 module Hasura.RQL.DML.Select.Internal
   ( mkSQLSelect
   , mkAggSelect
+  -- , mkConnectionSelect
+  -- , JoinCandidate(..)
   , module Hasura.RQL.DML.Select.Types
   )
 where
@@ -426,6 +428,39 @@ aggSelToArrNode pfxs als aggSel =
 
     subQueryReq = hasAggFld aggFlds
 
+-- connectionSelToArrNode
+--   :: Prefixes -> FieldName -> ArrRelConnection S.SQLExp -> ArrNode
+-- connectionSelToArrNode pfxs als aggSel =
+--   ArrNode [extr] colMapping mergedBN
+--   where
+--     AnnRelG _ colMapping annSel = aggSel
+--     AnnSelG aggFlds tabFrm tabPerm tabArgs strfyNum = annSel
+--     fldAls = S.Alias $ toIden als
+
+--     extr = flip S.Extractor (Just fldAls) $ S.applyJsonBuildObj $
+--            concatMap selFldToExtr aggFlds
+
+--     permLimit = _tpLimit tabPerm
+--     ordBy = _bnOrderBy mergedBN
+
+--     allBNs = map mkAggBaseNode aggFlds
+--     emptyBN = mkEmptyBaseNode (_pfThis pfxs) tabFrm
+--     mergedBN = foldr mergeBaseNodes emptyBN allBNs
+
+--     mkAggBaseNode (fn, selFld) =
+--       mkBaseNode subQueryReq pfxs fn selFld tabFrm tabPerm tabArgs strfyNum
+
+--     selFldToExtr (FieldName t, fld) = (:) (S.SELit t) $ pure $ case fld of
+--       TAFAgg flds -> aggFldToExp flds
+--       TAFNodes _  ->
+--         withJsonAggExtr subQueryReq permLimit ordBy $ S.Alias $ Iden t
+--       TAFExp e    ->
+--         -- bool_or to force aggregation
+--         S.SEFnApp "coalesce"
+--         [ S.SELit e , S.SEUnsafe "bool_or('true')::text"] Nothing
+
+--     subQueryReq = hasAggFld aggFlds
+
 hasAggFld :: Foldable t => t (a, TableAggFldG v) -> Bool
 hasAggFld = any (isTabAggFld . snd)
   where
@@ -534,6 +569,7 @@ mkBaseNode
   -> BaseNode
 mkBaseNode subQueryReq pfxs fldAls annSelFlds selectFrom
            tablePerm tableArgs strfyNum =
+
   BaseNode thisPfx distExprM fromItem finalWhere ordByExpM finalLimit offsetM
   allExtrs allObjsWithOb allArrsWithOb computedFields
   where
@@ -682,6 +718,7 @@ mkArrNode subQueryReq pfxs (fldName, annArrSel) = case annArrSel of
     in ArrNode [extr] (aarMapping annArrRel) bn
 
   ASAgg annAggSel -> aggSelToArrNode pfxs fldName annAggSel
+  -- TODO: ASConnection connectionSel -> connectionSelToArrNode pfxs fldName connectionSel
 
 injectJoinCond :: S.BoolExp       -- ^ Join condition
                -> S.BoolExp -- ^ Where condition
@@ -754,6 +791,119 @@ baseNodeToSel joinCond baseNode =
                 }
       in S.mkLateralFromItem sel als
 
+-- mkConnectionSelect :: ConnectionSelect S.SQLExp -> S.Select
+-- mkConnectionSelect annConnectionSel =
+--   prefixNumToAliases $ arrNodeToSelect bn extr $ S.BELit True
+--   where
+--     connectionSelect = AnnRelG rootRelName HM.empty annConnectionSel
+--     rootIden = Iden "root"
+--     rootPrefix = Prefixes rootIden rootIden
+--     ArrNode extr _ bn =
+--       connectionSelToArrNode rootPrefix (FieldName "root") connectionSelect
+
+data TableSource
+  = TableSource
+    { _tsFrom       :: !SelectFrom
+    , _tsPermission :: !TablePerm
+    , _tsArgs       :: !TableArgs
+    }
+  deriving (Show, Eq, Generic)
+instance Hashable TableSource
+
+
+-- data TableSource
+--   = TableSource
+--     { _tsFrom   :: !S.FromItem
+--     , _tsAlias  :: !S.Alias
+--     , _tsWhere  :: !S.BoolExp
+--     , _tsLimit  :: !(Maybe Int)
+--     , _tsOffset :: !(Maybe S.SQLExp)
+--     -- , _tsArgs       :: !TableArgs
+--     }
+--   deriving (Show, Eq, Generic)
+
+
+data BuildState
+  = BuildState
+    { _bsAliasGenerator  :: !Int
+    , _bsJoinTree        :: !JoinTree
+    }
+
+type Build = State BuildState
+
+-- | this is need in those cases where you need a single row when the table
+-- returns multiple
+forceAggregation :: S.SQLExp -> S.SQLExp
+forceAggregation e =
+  S.SEFnApp "coalesce" [ e, S.SEUnsafe "bool_or('true')::text"] Nothing
+
+-- | Returns the SQL expression that will construct the response
+-- for given field
+buildConnectionFieldExpression
+  :: S.Alias
+  -- ^ The table alias
+  -> ConnectionField S.SQLExp
+  -> Build S.SQLExp
+buildConnectionFieldExpression tableAlias = \case
+  ConnectionTypename typename -> pure $ forceAggregation $ S.SELit typename
+  ConnectionPageInfo fields ->
+    pure $ S.SELit "should be pageinfo"
+  ConnectionEdges fields -> do
+    fieldPairs <- forM fields $ \(fieldAlias, field) -> do
+      fieldExpression <- buildEdgeFieldExpression field
+      pure [S.SELit $ getFieldNameTxt fieldAlias, fieldExpression]
+    pure $ S.applyJsonBuildObj $ concat fieldPairs
+  where
+    buildEdgeFieldExpression = \case
+      EdgeTypename typename -> pure $ S.SELit typename
+      EdgeCursor -> pure $ S.SELit "will return a cursor"
+      EdgeNode fields -> undefined
+
+data Selector
+  = Selector !S.SQLExp !S.SQLExp
+  deriving (Show, Eq)
+
+-- | Returns the SQL expression that will construct the response
+-- for given field
+buildTableFieldExpression
+  :: S.Alias
+  -- ^ The table alias
+  -> AnnFldG S.SQLExp
+  -> Build S.SQLExp
+buildTableFieldExpression tableAlias = \case
+  FCol field -> undefined
+  FObj field -> undefined
+  FArr field -> undefined
+  FComputedField field -> undefined
+  FExp typename -> pure $ S.SELit typename
+
+processFields
+  :: ConnectionFields S.SQLExp
+  -> Maybe (NE.NonEmpty (AnnOrderByItemG S.SQLExp))
+  -> Build ()
+processFields = undefined
+
+mkSelectNode
+  :: ConnectionSelect S.SQLExp -> Build (TableSource, SelectNode)
+mkSelectNode = undefined
+
+data SelectNode
+  = SelectNode
+    { _jnColumns  :: !(HM.HashMap S.Alias S.SQLExp)
+    , _jnFrom     :: !S.FromItem
+    , _jnAlias    :: !S.Alias
+    , _jnJoinTree :: !JoinTree
+    , _jnWhere    :: !S.BoolExp
+    , _jnOrderBy  :: !(Maybe S.OrderByExp)
+    , _jnLimit    :: !(Maybe Int)
+    , _jnOffset   :: !(Maybe S.SQLExp)
+    }
+  deriving (Show, Eq)
+
+newtype JoinTree
+  = JoinTree { unJoinTree :: HM.HashMap TableSource SelectNode }
+  deriving (Show, Eq, Semigroup, Monoid)
+
 mkAggSelect :: AnnAggSel -> S.Select
 mkAggSelect annAggSel =
   prefixNumToAliases $ arrNodeToSelect bn extr $ S.BELit True
diff --git a/server/src-lib/Hasura/RQL/DML/Select/Types.hs b/server/src-lib/Hasura/RQL/DML/Select/Types.hs
index 8dc04963043eb..a078eb0f814e9 100644
--- a/server/src-lib/Hasura/RQL/DML/Select/Types.hs
+++ b/server/src-lib/Hasura/RQL/DML/Select/Types.hs
@@ -53,13 +53,15 @@ instance FromJSON ExtCol where
 data AnnAggOrdBy
   = AAOCount
   | AAOOp !T.Text !PGCol
-  deriving (Show, Eq)
+  deriving (Show, Eq, Generic)
+instance Hashable AnnAggOrdBy
 
 data AnnObColG v
   = AOCPG !PGCol
   | AOCObj !RelInfo !(AnnBoolExp v) !(AnnObColG v)
   | AOCAgg !RelInfo !(AnnBoolExp v) !AnnAggOrdBy
-  deriving (Show, Eq)
+  deriving (Show, Eq, Generic)
+instance (Hashable v) => Hashable (AnnObColG v)
 
 traverseAnnObCol
   :: (Applicative f)
@@ -99,6 +101,7 @@ type ObjSel = ObjSelG S.SQLExp
 
 type ArrRelG v = AnnRelG (AnnSimpleSelG v)
 type ArrRelAggG v = AnnRelG (AnnAggSelG v)
+type ArrRelConnection v = AnnRelG (ConnectionSelect v)
 type ArrRelAgg = ArrRelAggG S.SQLExp
 
 data ComputedFieldScalarSel v
@@ -127,6 +130,7 @@ type Fields a = [(FieldName, a)]
 data ArrSelG v
   = ASSimple !(ArrRelG v)
   | ASAgg !(ArrRelAggG v)
+  | ASConnection !(ArrRelConnection v)
   deriving (Show, Eq)
 
 traverseArrSel
@@ -137,6 +141,8 @@ traverseArrSel
 traverseArrSel f = \case
   ASSimple arrRel -> ASSimple <$> traverse (traverseAnnSimpleSel f) arrRel
   ASAgg arrRelAgg -> ASAgg <$> traverse (traverseAnnAggSel f) arrRelAgg
+  ASConnection relConnection ->
+    ASConnection <$> traverse (traverseConnectionSelect f) relConnection
 
 type ArrSel = ArrSelG S.SQLExp
 
@@ -193,7 +199,8 @@ data TableArgsG v
   , _taLimit    :: !(Maybe Int)
   , _taOffset   :: !(Maybe S.SQLExp)
   , _taDistCols :: !(Maybe (NE.NonEmpty PGCol))
-  } deriving (Show, Eq)
+  } deriving (Show, Eq, Generic)
+instance (Hashable v) => Hashable (TableArgsG v)
 
 traverseTableArgs
   :: (Applicative f)
@@ -247,6 +254,46 @@ data TableAggFldG v
   | TAFExp !T.Text
   deriving (Show, Eq)
 
+data PageInfoField
+  = PageInfoTypename !Text
+  | PageInfoHasNextPage
+  | PageInfoHasPreviousPage
+  | PageInfoStartCursor
+  | PageInfoEndCursor
+  deriving (Show, Eq)
+type PageInfoFields = Fields PageInfoField
+
+data EdgeField v
+  = EdgeTypename !Text
+  | EdgeCursor
+  | EdgeNode !(AnnFldsG v)
+  deriving (Show, Eq)
+type EdgeFields v = Fields (EdgeField v)
+
+traverseEdgeField
+  :: (Applicative f)
+  => (a -> f b) -> EdgeField a -> f (EdgeField b)
+traverseEdgeField f = \case
+  EdgeTypename t -> pure $ EdgeTypename t
+  EdgeCursor -> pure EdgeCursor
+  EdgeNode fields -> EdgeNode <$> traverseAnnFlds f fields
+
+data ConnectionField v
+  = ConnectionTypename !Text
+  | ConnectionPageInfo !PageInfoFields
+  | ConnectionEdges !(EdgeFields v)
+  deriving (Show, Eq)
+type ConnectionFields v = Fields (ConnectionField v)
+
+traverseConnectionField
+  :: (Applicative f)
+  => (a -> f b) -> ConnectionField a -> f (ConnectionField b)
+traverseConnectionField f = \case
+  ConnectionTypename t -> pure $ ConnectionTypename t
+  ConnectionPageInfo fields -> pure $ ConnectionPageInfo fields
+  ConnectionEdges fields ->
+    ConnectionEdges <$> traverse (traverse (traverseEdgeField f)) fields
+
 traverseTableAggFld
   :: (Applicative f)
   => (a -> f b) -> TableAggFldG a -> f (TableAggFldG b)
@@ -262,7 +309,8 @@ type TableAggFlds = TableAggFldsG S.SQLExp
 data ArgumentExp a
   = AETableRow !(Maybe Iden) -- ^ table row accessor
   | AEInput !a
-  deriving (Show, Eq, Functor, Foldable, Traversable)
+  deriving (Show, Eq, Functor, Foldable, Traversable, Generic)
+instance (Hashable v) => Hashable (ArgumentExp v)
 
 type FunctionArgsExpTableRow v = FunctionArgsExpG (ArgumentExp v)
 
@@ -271,8 +319,10 @@ data SelectFromG v
   | FromIden !Iden
   | FromFunction !QualifiedFunction
                  !(FunctionArgsExpTableRow v)
+                 -- a definition list
                  !(Maybe [(PGCol, PGScalarType)])
-  deriving (Show, Eq, Functor, Foldable, Traversable)
+  deriving (Show, Eq, Functor, Foldable, Traversable, Generic)
+instance (Hashable v) => Hashable (SelectFromG v)
 
 type SelectFrom = SelectFromG S.SQLExp
 
@@ -280,7 +330,8 @@ data TablePermG v
   = TablePerm
   { _tpFilter :: !(AnnBoolExp v)
   , _tpLimit  :: !(Maybe Int)
-  } deriving (Eq, Show)
+  } deriving (Eq, Show, Generic)
+instance (Hashable v) => Hashable (TablePermG v)
 
 traverseTablePerm
   :: (Applicative f)
@@ -341,19 +392,29 @@ type AnnSimpleSel = AnnSimpleSelG S.SQLExp
 type AnnAggSelG v = AnnSelG (TableAggFldsG v) v
 type AnnAggSel = AnnAggSelG S.SQLExp
 
+type ConnectionSelect v = AnnSelG (ConnectionFields v) v
+traverseConnectionSelect
+  :: (Applicative f)
+  => (a -> f b)
+  -> ConnectionSelect a -> f (ConnectionSelect b)
+traverseConnectionSelect f =
+  traverseAnnSel (traverse (traverse (traverseConnectionField f))) f
+
 data FunctionArgsExpG a
   = FunctionArgsExp
   { _faePositional :: ![a]
   , _faeNamed      :: !(HM.HashMap Text a)
-  } deriving (Show, Eq, Functor, Foldable, Traversable)
+  } deriving (Show, Eq, Functor, Foldable, Traversable, Generic)
+instance (Hashable a) => Hashable (FunctionArgsExpG a)
 
 emptyFunctionArgsExp :: FunctionArgsExpG a
 emptyFunctionArgsExp = FunctionArgsExp [] HM.empty
 
 type FunctionArgExp = FunctionArgsExpG S.SQLExp
 
--- | If argument positional index is less than or equal to length of 'positional' arguments then
--- insert the value in 'positional' arguments else insert the value with argument name in 'named' arguments
+-- | If argument positional index is less than or equal to length of
+-- 'positional' arguments then insert the value in 'positional' arguments else
+-- insert the value with argument name in 'named' arguments
 insertFunctionArg
   :: FunctionArgName
   -> Int
diff --git a/server/src-lib/Hasura/RQL/Types/BoolExp.hs b/server/src-lib/Hasura/RQL/Types/BoolExp.hs
index d37cd857e9d51..56b109bf1f278 100644
--- a/server/src-lib/Hasura/RQL/Types/BoolExp.hs
+++ b/server/src-lib/Hasura/RQL/Types/BoolExp.hs
@@ -63,6 +63,7 @@ data GExists a
 instance (NFData a) => NFData (GExists a)
 instance (Data a) => Plated (GExists a)
 instance (Cacheable a) => Cacheable (GExists a)
+instance (Hashable a) => Hashable (GExists a)
 
 gExistsToJSON :: (a -> (Text, Value)) -> GExists a -> Value
 gExistsToJSON f (GExists qt wh) =
@@ -89,6 +90,7 @@ data GBoolExp a
 instance (NFData a) => NFData (GBoolExp a)
 instance (Data a) => Plated (GBoolExp a)
 instance (Cacheable a) => Cacheable (GBoolExp a)
+instance (Hashable a) => Hashable (GBoolExp a)
 
 gBoolExpTrue :: GBoolExp a
 gBoolExpTrue = BoolAnd []
@@ -140,6 +142,7 @@ data DWithinGeomOp a =
   } deriving (Show, Eq, Functor, Foldable, Traversable, Generic, Data)
 instance (NFData a) => NFData (DWithinGeomOp a)
 instance (Cacheable a) => Cacheable (DWithinGeomOp a)
+instance (Hashable a) => Hashable (DWithinGeomOp a)
 $(deriveJSON (aesonDrop 6 snakeCase) ''DWithinGeomOp)
 
 data DWithinGeogOp a =
@@ -150,6 +153,7 @@ data DWithinGeogOp a =
   } deriving (Show, Eq, Functor, Foldable, Traversable, Generic, Data)
 instance (NFData a) => NFData (DWithinGeogOp a)
 instance (Cacheable a) => Cacheable (DWithinGeogOp a)
+instance (Hashable a) => Hashable (DWithinGeogOp a)
 $(deriveJSON (aesonDrop 6 snakeCase) ''DWithinGeogOp)
 
 data STIntersectsNbandGeommin a =
@@ -159,6 +163,7 @@ data STIntersectsNbandGeommin a =
   } deriving (Show, Eq, Functor, Foldable, Traversable, Generic, Data)
 instance (NFData a) => NFData (STIntersectsNbandGeommin a)
 instance (Cacheable a) => Cacheable (STIntersectsNbandGeommin a)
+instance (Hashable a) => Hashable (STIntersectsNbandGeommin a)
 $(deriveJSON (aesonDrop 4 snakeCase) ''STIntersectsNbandGeommin)
 
 data STIntersectsGeomminNband a =
@@ -168,6 +173,7 @@ data STIntersectsGeomminNband a =
   } deriving (Show, Eq, Functor, Foldable, Traversable, Generic, Data)
 instance (NFData a) => NFData (STIntersectsGeomminNband a)
 instance (Cacheable a) => Cacheable (STIntersectsGeomminNband a)
+instance (Hashable a) => Hashable (STIntersectsGeomminNband a)
 $(deriveJSON (aesonDrop 4 snakeCase) ''STIntersectsGeomminNband)
 
 type CastExp a = M.HashMap PGScalarType [OpExpG a]
@@ -227,6 +233,7 @@ data OpExpG a
   deriving (Eq, Show, Functor, Foldable, Traversable, Generic, Data)
 instance (NFData a) => NFData (OpExpG a)
 instance (Cacheable a) => Cacheable (OpExpG a)
+instance (Hashable a) => Hashable (OpExpG a)
 
 opExpDepCol :: OpExpG a -> Maybe PGCol
 opExpDepCol = \case
@@ -300,6 +307,7 @@ data AnnBoolExpFld a
   deriving (Show, Eq, Functor, Foldable, Traversable, Generic)
 instance (NFData a) => NFData (AnnBoolExpFld a)
 instance (Cacheable a) => Cacheable (AnnBoolExpFld a)
+instance (Hashable a) => Hashable (AnnBoolExpFld a)
 
 type AnnBoolExp a
   = GBoolExp (AnnBoolExpFld a)
diff --git a/server/src-lib/Hasura/RQL/Types/Column.hs b/server/src-lib/Hasura/RQL/Types/Column.hs
index 7c4e2ff81e588..16e36f8c417f0 100644
--- a/server/src-lib/Hasura/RQL/Types/Column.hs
+++ b/server/src-lib/Hasura/RQL/Types/Column.hs
@@ -167,6 +167,7 @@ data PGColumnInfo
   } deriving (Show, Eq, Generic)
 instance NFData PGColumnInfo
 instance Cacheable PGColumnInfo
+instance Hashable PGColumnInfo
 $(deriveToJSON (aesonDrop 3 snakeCase) ''PGColumnInfo)
 
 onlyIntCols :: [PGColumnInfo] -> [PGColumnInfo]
diff --git a/server/src-lib/Hasura/RQL/Types/Common.hs b/server/src-lib/Hasura/RQL/Types/Common.hs
index fccf29a13a298..27cf5f06da93c 100644
--- a/server/src-lib/Hasura/RQL/Types/Common.hs
+++ b/server/src-lib/Hasura/RQL/Types/Common.hs
@@ -142,6 +142,7 @@ data RelInfo
   } deriving (Show, Eq, Generic)
 instance NFData RelInfo
 instance Cacheable RelInfo
+instance Hashable RelInfo
 $(deriveToJSON (aesonDrop 2 snakeCase) ''RelInfo)
 
 newtype FieldName
diff --git a/server/src-lib/Hasura/RQL/Types/DML.hs b/server/src-lib/Hasura/RQL/Types/DML.hs
index 7851770f2fb61..e19e54369880f 100644
--- a/server/src-lib/Hasura/RQL/Types/DML.hs
+++ b/server/src-lib/Hasura/RQL/Types/DML.hs
@@ -101,6 +101,7 @@ instance (FromJSON a) => FromJSON (DMLQuery a) where
 newtype OrderType
   = OrderType { unOrderType :: S.OrderType }
   deriving (Show, Eq, Lift, Generic)
+instance Hashable OrderType
 
 instance FromJSON OrderType where
   parseJSON =
@@ -112,6 +113,7 @@ instance FromJSON OrderType where
 newtype NullsOrder
   = NullsOrder { unNullsOrder :: S.NullsOrder }
   deriving (Show, Eq, Lift, Generic)
+instance Hashable NullsOrder
 
 instance FromJSON NullsOrder where
   parseJSON =
@@ -176,7 +178,8 @@ data OrderByItemG a
   { obiType   :: !(Maybe OrderType)
   , obiColumn :: !a
   , obiNulls  :: !(Maybe NullsOrder)
-  } deriving (Show, Eq, Lift, Functor, Foldable, Traversable)
+  } deriving (Show, Eq, Lift, Functor, Foldable, Traversable, Generic)
+instance (Hashable a) => Hashable (OrderByItemG a)
 
 type OrderByItem = OrderByItemG OrderByCol
 
diff --git a/server/src-lib/Hasura/SQL/DML.hs b/server/src-lib/Hasura/SQL/DML.hs
index 3449501f77413..8e1b3a67117f9 100644
--- a/server/src-lib/Hasura/SQL/DML.hs
+++ b/server/src-lib/Hasura/SQL/DML.hs
@@ -35,6 +35,7 @@ data Select
     } deriving (Show, Eq, Generic, Data)
 instance NFData Select
 instance Cacheable Select
+instance Hashable Select
 
 mkSelect :: Select
 mkSelect = Select Nothing [] Nothing
@@ -43,7 +44,7 @@ mkSelect = Select Nothing [] Nothing
 
 newtype LimitExp
   = LimitExp SQLExp
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 instance ToSQL LimitExp where
   toSQL (LimitExp se) =
@@ -51,7 +52,7 @@ instance ToSQL LimitExp where
 
 newtype OffsetExp
   = OffsetExp SQLExp
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 instance ToSQL OffsetExp where
   toSQL (OffsetExp se) =
@@ -59,7 +60,7 @@ instance ToSQL OffsetExp where
 
 newtype OrderByExp
   = OrderByExp [OrderByItem]
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 data OrderByItem
   = OrderByItem
@@ -69,6 +70,7 @@ data OrderByItem
     } deriving (Show, Eq, Generic, Data)
 instance NFData OrderByItem
 instance Cacheable OrderByItem
+instance Hashable OrderByItem
 
 instance ToSQL OrderByItem where
   toSQL (OrderByItem e ot no) =
@@ -78,6 +80,7 @@ data OrderType = OTAsc | OTDesc
   deriving (Show, Eq, Lift, Generic, Data)
 instance NFData OrderType
 instance Cacheable OrderType
+instance Hashable OrderType
 
 instance ToSQL OrderType where
   toSQL OTAsc  = "ASC"
@@ -89,6 +92,7 @@ data NullsOrder
   deriving (Show, Eq, Lift, Generic, Data)
 instance NFData NullsOrder
 instance Cacheable NullsOrder
+instance Hashable NullsOrder
 
 instance ToSQL NullsOrder where
   toSQL NFirst = "NULLS FIRST"
@@ -100,7 +104,7 @@ instance ToSQL OrderByExp where
 
 newtype GroupByExp
   = GroupByExp [SQLExp]
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 instance ToSQL GroupByExp where
   toSQL (GroupByExp idens) =
@@ -108,7 +112,7 @@ instance ToSQL GroupByExp where
 
 newtype FromExp
   = FromExp [FromItem]
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 instance ToSQL FromExp where
   toSQL (FromExp items) =
@@ -148,7 +152,7 @@ mkRowExp extrs = let
 
 newtype HavingExp
   = HavingExp BoolExp
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 instance ToSQL HavingExp where
   toSQL (HavingExp be) =
@@ -156,7 +160,7 @@ instance ToSQL HavingExp where
 
 newtype WhereFrag
   = WhereFrag { getWFBoolExp :: BoolExp }
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 instance ToSQL WhereFrag where
   toSQL (WhereFrag be) =
@@ -188,6 +192,7 @@ data Qual
   deriving (Show, Eq, Generic, Data)
 instance NFData Qual
 instance Cacheable Qual
+instance Hashable Qual
 
 mkQual :: QualifiedTable -> Qual
 mkQual = QualTable
@@ -205,6 +210,7 @@ data QIden
   deriving (Show, Eq, Generic, Data)
 instance NFData QIden
 instance Cacheable QIden
+instance Hashable QIden
 
 instance ToSQL QIden where
   toSQL (QIden qual iden) =
@@ -212,7 +218,7 @@ instance ToSQL QIden where
 
 newtype SQLOp
   = SQLOp {sqlOpTxt :: T.Text}
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 incOp :: SQLOp
 incOp = SQLOp "+"
@@ -234,7 +240,7 @@ jsonbDeleteAtPathOp = SQLOp "#-"
 
 newtype TypeAnn
   = TypeAnn { unTypeAnn :: T.Text }
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 instance ToSQL TypeAnn where
   toSQL (TypeAnn ty) = "::" <> TB.text ty
@@ -264,6 +270,7 @@ data CountType
   deriving (Show, Eq, Generic, Data)
 instance NFData CountType
 instance Cacheable CountType
+instance Hashable CountType
 
 instance ToSQL CountType where
   toSQL CTStar            = "*"
@@ -274,7 +281,7 @@ instance ToSQL CountType where
 
 newtype TupleExp
   = TupleExp [SQLExp]
-  deriving (Show, Eq, NFData, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 instance ToSQL TupleExp where
   toSQL (TupleExp exps) =
@@ -306,6 +313,7 @@ data SQLExp
   deriving (Show, Eq, Generic, Data)
 instance NFData SQLExp
 instance Cacheable SQLExp
+instance Hashable SQLExp
 
 withTyAnn :: PGScalarType -> SQLExp -> SQLExp
 withTyAnn colTy v = SETyAnn v . mkTypeAnn $ PGTypeScalar colTy
@@ -315,7 +323,7 @@ instance J.ToJSON SQLExp where
 
 newtype Alias
   = Alias { getAlias :: Iden }
-  deriving (Show, Eq, NFData, Hashable, Data, Cacheable)
+  deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 instance IsIden Alias where
   toIden (Alias iden) = iden
@@ -381,6 +389,7 @@ data Extractor = Extractor !SQLExp !(Maybe Alias)
   deriving (Show, Eq, Generic, Data)
 instance NFData Extractor
 instance Cacheable Extractor
+instance Hashable Extractor
 
 mkSQLOpExp
   :: SQLOp
@@ -428,6 +437,7 @@ data DistinctExpr
   deriving (Show, Eq, Generic, Data)
 instance NFData DistinctExpr
 instance Cacheable DistinctExpr
+instance Hashable DistinctExpr
 
 instance ToSQL DistinctExpr where
   toSQL DistinctSimple    = "DISTINCT"
@@ -441,6 +451,7 @@ data FunctionArgs
   } deriving (Show, Eq, Generic, Data)
 instance NFData FunctionArgs
 instance Cacheable FunctionArgs
+instance Hashable FunctionArgs
 
 instance ToSQL FunctionArgs where
   toSQL (FunctionArgs positionalArgs namedArgsMap) =
@@ -455,6 +466,7 @@ data DefinitionListItem
   } deriving (Show, Eq, Data, Generic)
 instance NFData DefinitionListItem
 instance Cacheable DefinitionListItem
+instance Hashable DefinitionListItem
 
 instance ToSQL DefinitionListItem where
   toSQL (DefinitionListItem column columnType) =
@@ -467,6 +479,7 @@ data FunctionAlias
   } deriving (Show, Eq, Data, Generic)
 instance NFData FunctionAlias
 instance Cacheable FunctionAlias
+instance Hashable FunctionAlias
 
 mkSimpleFunctionAlias :: Iden -> FunctionAlias
 mkSimpleFunctionAlias identifier =
@@ -491,6 +504,7 @@ data FunctionExp
   } deriving (Show, Eq, Generic, Data)
 instance NFData FunctionExp
 instance Cacheable FunctionExp
+instance Hashable FunctionExp
 
 instance ToSQL FunctionExp where
   toSQL (FunctionExp qf args alsM) =
@@ -507,6 +521,7 @@ data FromItem
   deriving (Show, Eq, Generic, Data)
 instance NFData FromItem
 instance Cacheable FromItem
+instance Hashable FromItem
 
 mkSelFromItem :: Select -> Alias -> FromItem
 mkSelFromItem = FISelect (Lateral False)
@@ -536,7 +551,7 @@ instance ToSQL FromItem where
     toSQL je
 
 newtype Lateral = Lateral Bool
-  deriving (Show, Eq, Data, NFData, Cacheable)
+  deriving (Show, Eq, Data, NFData, Cacheable, Hashable)
 
 instance ToSQL Lateral where
   toSQL (Lateral True)  = "LATERAL"
@@ -551,6 +566,7 @@ data JoinExpr
   } deriving (Show, Eq, Generic, Data)
 instance NFData JoinExpr
 instance Cacheable JoinExpr
+instance Hashable JoinExpr
 
 instance ToSQL JoinExpr where
   toSQL je =
@@ -567,6 +583,7 @@ data JoinType
   deriving (Eq, Show, Generic, Data)
 instance NFData JoinType
 instance Cacheable JoinType
+instance Hashable JoinType
 
 instance ToSQL JoinType where
   toSQL Inner      = "INNER JOIN"
@@ -580,6 +597,7 @@ data JoinCond
   deriving (Show, Eq, Generic, Data)
 instance NFData JoinCond
 instance Cacheable JoinCond
+instance Hashable JoinCond
 
 instance ToSQL JoinCond where
   toSQL (JoinOn be) =
@@ -603,6 +621,7 @@ data BoolExp
   deriving (Show, Eq, Generic, Data)
 instance NFData BoolExp
 instance Cacheable BoolExp
+instance Hashable BoolExp
 
 -- removes extraneous 'AND true's
 simplifyBoolExp :: BoolExp -> BoolExp
@@ -658,6 +677,7 @@ data BinOp = AndOp | OrOp
   deriving (Show, Eq, Generic, Data)
 instance NFData BinOp
 instance Cacheable BinOp
+instance Hashable BinOp
 
 instance ToSQL BinOp where
   toSQL AndOp = "AND"
@@ -686,6 +706,7 @@ data CompareOp
   deriving (Eq, Generic, Data)
 instance NFData CompareOp
 instance Cacheable CompareOp
+instance Hashable CompareOp
 
 instance Show CompareOp where
   show = \case
@@ -832,7 +853,7 @@ instance ToSQL SQLConflict where
 
 newtype ValuesExp
   = ValuesExp [TupleExp]
-  deriving (Show, Eq, Data, NFData, Cacheable)
+  deriving (Show, Eq, Data, NFData, Cacheable, Hashable)
 
 instance ToSQL ValuesExp where
   toSQL (ValuesExp tuples) =
diff --git a/server/src-lib/Hasura/SQL/Types.hs b/server/src-lib/Hasura/SQL/Types.hs
index 3769a5f6f052f..cd7a634763dd2 100644
--- a/server/src-lib/Hasura/SQL/Types.hs
+++ b/server/src-lib/Hasura/SQL/Types.hs
@@ -303,7 +303,7 @@ type QualifiedFunction = QualifiedObject FunctionName
 
 newtype PGDescription
   = PGDescription { getPGDescription :: T.Text }
-  deriving (Show, Eq, FromJSON, ToJSON, Q.FromCol, NFData, Cacheable)
+  deriving (Show, Eq, FromJSON, ToJSON, Q.FromCol, NFData, Cacheable, Hashable)
 
 newtype PGCol
   = PGCol { getPGColTxt :: T.Text }

From a16bc0bfd94c5bd0a52cc0ae80b9a5735396ffa5 Mon Sep 17 00:00:00 2001
From: rakeshkky <12475069+rakeshkky@users.noreply.github.com>
Date: Wed, 29 Apr 2020 18:29:33 +0530
Subject: [PATCH 03/29] implement 'mkConnectionSelect' function with minimal
 cursors.

---
 server/src-lib/Hasura/GraphQL/Resolve.hs      |  14 +-
 .../src-lib/Hasura/GraphQL/Resolve/Select.hs  |  10 +-
 .../src-lib/Hasura/GraphQL/Resolve/Types.hs   |   4 +-
 server/src-lib/Hasura/GraphQL/Schema.hs       |   5 +-
 server/src-lib/Hasura/RQL/DDL/Schema/Cache.hs |   1 -
 server/src-lib/Hasura/RQL/DML/Select.hs       |   3 +-
 .../src-lib/Hasura/RQL/DML/Select/Internal.hs | 157 +++++++++++-------
 server/src-lib/Hasura/RQL/DML/Select/Types.hs |   4 +-
 server/src-lib/Hasura/RQL/Types/Common.hs     |   4 +-
 9 files changed, 120 insertions(+), 82 deletions(-)

diff --git a/server/src-lib/Hasura/GraphQL/Resolve.hs b/server/src-lib/Hasura/GraphQL/Resolve.hs
index 3e4b03357d4e9..7f3404f63a569 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve.hs
@@ -44,7 +44,7 @@ data QueryRootFldAST v
   = QRFPk !(DS.AnnSimpleSelG v)
   | QRFSimple !(DS.AnnSimpleSelG v)
   | QRFAgg !(DS.AnnAggSelG v)
-  | QRFConnection !(DS.ConnectionSelect v)
+  | QRFConnection !(Maybe (NonEmpty PGCol)) !(DS.ConnectionSelect v)
   | QRFActionSelect !(DS.AnnSimpleSelG v)
   deriving (Show, Eq)
 
@@ -60,7 +60,7 @@ traverseQueryRootFldAST f = \case
   QRFPk s           -> QRFPk <$> DS.traverseAnnSimpleSel f s
   QRFSimple s       -> QRFSimple <$> DS.traverseAnnSimpleSel f s
   QRFAgg s          -> QRFAgg <$> DS.traverseAnnAggSel f s
-  QRFConnection s   -> QRFConnection <$> DS.traverseConnectionSelect f s
+  QRFConnection pkey s   -> QRFConnection pkey <$> DS.traverseConnectionSelect f s
   QRFActionSelect s -> QRFActionSelect <$> DS.traverseAnnSimpleSel f s
 
 toPGQuery :: QueryRootFldResolved -> Q.Query
@@ -69,7 +69,7 @@ toPGQuery = \case
   QRFSimple s       -> DS.selectQuerySQL DS.JASMultipleRows s
   QRFAgg s          -> DS.selectAggQuerySQL s
   QRFActionSelect s -> DS.selectQuerySQL DS.JASSingleObject s
-  QRFConnection s   -> Q.fromBuilder $ toSQL $ DS.mkConnectionSelect s
+  QRFConnection pkey s   -> Q.fromBuilder $ toSQL $ DS.mkConnectionSelect pkey s
 
 validateHdrs
   :: (Foldable t, QErrM m) => UserInfo -> t Text -> m ()
@@ -107,10 +107,10 @@ queryFldToPGAST fld = do
       QRFAgg <$> RS.convertFuncQueryAgg ctx fld
     QCActionFetch ctx ->
       QRFActionSelect <$> RA.resolveAsyncActionQuery userInfo ctx fld
-    QCSelectConnection ctx -> do
-      QRFConnection <$> RS.convertConnectionSelect ctx fld
-    QCFuncConnection ctx -> do
-      QRFConnection <$> RS.convertConnectionFuncQuery ctx fld
+    QCSelectConnection pk ctx ->
+      QRFConnection pk <$> RS.convertConnectionSelect ctx fld
+    QCFuncConnection pk ctx ->
+      QRFConnection pk <$> RS.convertConnectionFuncQuery ctx fld
 
 mutFldToTx
   :: ( HasVersion
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Select.hs b/server/src-lib/Hasura/GraphQL/Resolve/Select.hs
index 5b9aaca18e0dc..c31072f9e3d9c 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Select.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Select.hs
@@ -170,14 +170,14 @@ parsePageInfoSelectionSet
 parsePageInfoSelectionSet fldTy selSet =
   fmap toFields $ withSelSet selSet $ \f ->
     case _fName f of
-      "__typename"  -> pure $ RS.PageInfoTypename $ G.unName $ G.unNamedType fldTy
-      "hasNextPage" -> pure $ RS.PageInfoHasNextPage
+      "__typename"      -> pure $ RS.PageInfoTypename $ G.unName $ G.unNamedType fldTy
+      "hasNextPage"     -> pure $ RS.PageInfoHasNextPage
       "hasPreviousPage" -> pure $ RS.PageInfoHasPreviousPage
-      "startCursor" -> pure $ RS.PageInfoStartCursor
-      "endCursor" -> pure $ RS.PageInfoEndCursor
+      "startCursor"     -> pure $ RS.PageInfoStartCursor
+      "endCursor"       -> pure $ RS.PageInfoEndCursor
       -- "aggregate"  -> RS.TAFAgg <$> convertAggFld colGNameMap fTy fSelSet
       -- "nodes"      -> RS.TAFNodes <$> processTableSelectionSet fTy fSelSet
-      G.Name t     -> throw500 $ "unexpected field in PageInfo node: " <> t
+      G.Name t          -> throw500 $ "unexpected field in PageInfo node: " <> t
 
 type TableArgs = RS.TableArgsG UnresolvedVal
 
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Types.hs b/server/src-lib/Hasura/GraphQL/Resolve/Types.hs
index 3dda96769d2ed..297778a9a0e62 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Types.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Types.hs
@@ -29,12 +29,12 @@ import qualified Hasura.SQL.DML                 as S
 
 data QueryCtx
   = QCSelect !SelOpCtx
-  | QCSelectConnection !SelOpCtx
+  | QCSelectConnection !(Maybe (NonEmpty PGCol)) !SelOpCtx
   | QCSelectPkey !SelPkOpCtx
   | QCSelectAgg !SelOpCtx
   | QCFuncQuery !FuncQOpCtx
   | QCFuncAggQuery !FuncQOpCtx
-  | QCFuncConnection !FuncQOpCtx
+  | QCFuncConnection !(Maybe (NonEmpty PGCol)) !FuncQOpCtx
   | QCActionFetch !ActionSelectOpContext
   deriving (Show, Eq)
 
diff --git a/server/src-lib/Hasura/GraphQL/Schema.hs b/server/src-lib/Hasura/GraphQL/Schema.hs
index 0126f01838fb6..af1ac0082fd29 100644
--- a/server/src-lib/Hasura/GraphQL/Schema.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema.hs
@@ -363,6 +363,7 @@ getRootFldsRole' tn primaryKey constraints fields funcs insM
         ]
     }
   where
+    primaryKeyColumn = fmap (fmap pgiColumn . _pkColumns) primaryKey
     makeFieldMap = mapFromL (_fiName . snd)
     customRootFields = _tcCustomRootFields tableConfig
     colGNameMap = mkPGColGNameMap $ getCols fields
@@ -421,7 +422,7 @@ getRootFldsRole' tn primaryKey constraints fields funcs insM
     getSelDet (selFltr, pLimit, hdrs, _) =
       selFldHelper QCSelect (mkSelFld selCustName) selFltr pLimit hdrs
     getSelConnectionDet (selFltr, pLimit, hdrs, _) =
-      selFldHelper QCSelectConnection (mkSelFldConnection Nothing) selFltr pLimit hdrs
+      selFldHelper (QCSelectConnection primaryKeyColumn) (mkSelFldConnection Nothing) selFltr pLimit hdrs
 
     selAggCustName = getCustomNameWith _tcrfSelectAggregate
     getSelAggDet (Just (selFltr, pLimit, hdrs, True)) =
@@ -445,7 +446,7 @@ getRootFldsRole' tn primaryKey constraints fields funcs insM
       funcFldHelper QCFuncQuery mkFuncQueryFld selFltr pLimit hdrs
 
     getFuncQueryConnectionFlds (selFltr, pLimit, hdrs, _) =
-      funcFldHelper QCFuncConnection mkFuncQueryConnectionFld selFltr pLimit hdrs
+      funcFldHelper (QCFuncConnection primaryKeyColumn) mkFuncQueryConnectionFld selFltr pLimit hdrs
 
     getFuncAggQueryFlds (selFltr, pLimit, hdrs, True) =
       funcFldHelper QCFuncAggQuery mkFuncAggQueryFld selFltr pLimit hdrs
diff --git a/server/src-lib/Hasura/RQL/DDL/Schema/Cache.hs b/server/src-lib/Hasura/RQL/DDL/Schema/Cache.hs
index 25329e7417535..ee37fafc15cde 100644
--- a/server/src-lib/Hasura/RQL/DDL/Schema/Cache.hs
+++ b/server/src-lib/Hasura/RQL/DDL/Schema/Cache.hs
@@ -258,7 +258,6 @@ buildSchemaCacheRule = proc (catalogMetadata, invalidationKeys) -> do
       -- custom types
       resolvedCustomTypes <- bindA -< resolveCustomTypes tableCache customTypes
 
-      -- actions
       actionCache <- (mapFromL _amName actions >- returnA)
         >-> (| Inc.keyed (\_ action -> do
                let ActionMetadata name comment def actionPermissions = action
diff --git a/server/src-lib/Hasura/RQL/DML/Select.hs b/server/src-lib/Hasura/RQL/DML/Select.hs
index 9a21d761919c5..ab8a892b435b2 100644
--- a/server/src-lib/Hasura/RQL/DML/Select.hs
+++ b/server/src-lib/Hasura/RQL/DML/Select.hs
@@ -265,8 +265,7 @@ convSelectQuery sessVarBldr prepArgBuilder (DMLQuery qt selQ) = do
   let fieldInfo = _tciFieldInfoMap $ _tiCoreInfo tabInfo
   extSelQ <- resolveStar fieldInfo selPermInfo selQ
   validateHeaders $ spiRequiredHeaders selPermInfo
-  convSelectQ fieldInfo selPermInfo
-    extSelQ sessVarBldr prepArgBuilder
+  convSelectQ fieldInfo selPermInfo extSelQ sessVarBldr prepArgBuilder
 
 selectP2 :: JsonAggSelect -> (AnnSimpleSel, DS.Seq Q.PrepArg) -> Q.TxE QErr EncJSON
 selectP2 jsonAggSelect (sel, p) =
diff --git a/server/src-lib/Hasura/RQL/DML/Select/Internal.hs b/server/src-lib/Hasura/RQL/DML/Select/Internal.hs
index 360c5a4245108..cc8a1cca362de 100644
--- a/server/src-lib/Hasura/RQL/DML/Select/Internal.hs
+++ b/server/src-lib/Hasura/RQL/DML/Select/Internal.hs
@@ -3,11 +3,13 @@ module Hasura.RQL.DML.Select.Internal
   , mkAggSelect
   -- , mkConnectionSelect
   -- , JoinCandidate(..)
+  , mkConnectionSelect
   , module Hasura.RQL.DML.Select.Types
   )
 where
 
 import           Control.Lens                hiding (op)
+import           Control.Monad.Writer.Strict
 import           Data.List                   (delete, sort)
 import           Instances.TH.Lift           ()
 
@@ -364,7 +366,7 @@ processAnnOrderByCol pfx parAls arrRelCtx strfyNum = \case
         (extr, arrFlds) = mkAggObExtrAndFlds annAggOb
         selFld = TAFAgg arrFlds
         bn = mkBaseNode False (Prefixes arrPfx pfx) fldName selFld tabFrom
-             tabPerm noTableArgs strfyNum
+             tabPerm noTableArgs Nothing strfyNum
         aggNode = ArrNode [extr] colMapping $ mergeBaseNodes bn $
                   mkEmptyBaseNode arrPfx tabFrom
         obAls = arrPfx <> Iden "." <> toIden fldName
@@ -415,7 +417,7 @@ aggSelToArrNode pfxs als aggSel =
     mergedBN = foldr mergeBaseNodes emptyBN allBNs
 
     mkAggBaseNode (fn, selFld) =
-      mkBaseNode subQueryReq pfxs fn selFld tabFrm tabPerm tabArgs strfyNum
+      mkBaseNode subQueryReq pfxs fn selFld tabFrm tabPerm tabArgs Nothing strfyNum
 
     selFldToExtr (FieldName t, fld) = (:) (S.SELit t) $ pure $ case fld of
       TAFAgg flds -> aggFldToExp flds
@@ -428,39 +430,6 @@ aggSelToArrNode pfxs als aggSel =
 
     subQueryReq = hasAggFld aggFlds
 
--- connectionSelToArrNode
---   :: Prefixes -> FieldName -> ArrRelConnection S.SQLExp -> ArrNode
--- connectionSelToArrNode pfxs als aggSel =
---   ArrNode [extr] colMapping mergedBN
---   where
---     AnnRelG _ colMapping annSel = aggSel
---     AnnSelG aggFlds tabFrm tabPerm tabArgs strfyNum = annSel
---     fldAls = S.Alias $ toIden als
-
---     extr = flip S.Extractor (Just fldAls) $ S.applyJsonBuildObj $
---            concatMap selFldToExtr aggFlds
-
---     permLimit = _tpLimit tabPerm
---     ordBy = _bnOrderBy mergedBN
-
---     allBNs = map mkAggBaseNode aggFlds
---     emptyBN = mkEmptyBaseNode (_pfThis pfxs) tabFrm
---     mergedBN = foldr mergeBaseNodes emptyBN allBNs
-
---     mkAggBaseNode (fn, selFld) =
---       mkBaseNode subQueryReq pfxs fn selFld tabFrm tabPerm tabArgs strfyNum
-
---     selFldToExtr (FieldName t, fld) = (:) (S.SELit t) $ pure $ case fld of
---       TAFAgg flds -> aggFldToExp flds
---       TAFNodes _  ->
---         withJsonAggExtr subQueryReq permLimit ordBy $ S.Alias $ Iden t
---       TAFExp e    ->
---         -- bool_or to force aggregation
---         S.SEFnApp "coalesce"
---         [ S.SELit e , S.SEUnsafe "bool_or('true')::text"] Nothing
-
---     subQueryReq = hasAggFld aggFlds
-
 hasAggFld :: Foldable t => t (a, TableAggFldG v) -> Bool
 hasAggFld = any (isTabAggFld . snd)
   where
@@ -557,6 +526,17 @@ mkOrdByItems pfx fldAls orderByM strfyNum arrRelCtx =
     getOrdByAggNode (OBNArrNode als node) = Just (als, node)
     getOrdByAggNode _                     = Nothing
 
+cursorAlias :: S.Alias
+cursorAlias = S.Alias $ Iden "__cursor"
+
+mkCursorExtractor :: Iden -> [PGCol] -> S.SQLExp
+mkCursorExtractor pfx columns =
+  flip S.SETyAnn S.textTypeAnn $
+  S.applyJsonBuildObj $ flip concatMap columns $
+  \column -> [ S.SELit $ getPGColTxt column
+             , S.mkQIdenExp (mkBaseTableAls pfx) column
+             ]
+
 mkBaseNode
   :: Bool
   -> Prefixes
@@ -565,10 +545,11 @@ mkBaseNode
   -> SelectFrom
   -> TablePerm
   -> TableArgs
+  -> Maybe (NonEmpty PGCol)
   -> Bool
   -> BaseNode
 mkBaseNode subQueryReq pfxs fldAls annSelFlds selectFrom
-           tablePerm tableArgs strfyNum =
+           tablePerm tableArgs primaryKeyColumns strfyNum =
 
   BaseNode thisPfx distExprM fromItem finalWhere ordByExpM finalLimit offsetM
   allExtrs allObjsWithOb allArrsWithOb computedFields
@@ -599,6 +580,8 @@ mkBaseNode subQueryReq pfxs fldAls annSelFlds selectFrom
           let arrFlds = mapMaybe getAnnArr flds
               arrRelCtx = mkArrRelCtx arrFlds
               selExtr = buildJsonObject thisPfx fldAls arrRelCtx strfyNum flds
+              cursorExtrs = maybe [] (pure . (cursorAlias,) . mkCursorExtractor thisPfx . toList)
+                            primaryKeyColumns
               -- all object relationships
               objNodes = HM.fromListWith mergeObjNodes $
                         map mkObjItem (mapMaybe getAnnObj flds)
@@ -614,7 +597,7 @@ mkBaseNode subQueryReq pfxs fldAls annSelFlds selectFrom
               allObjs = HM.unionWith mergeObjNodes objNodes ordByObjs
               allArrs = HM.unionWith mergeArrNodes arrNodes ordByArrs
 
-          in ( HM.fromList $ selExtr:obExtrs <> distExtrs
+          in ( HM.fromList $ selExtr:obExtrs <> distExtrs <> cursorExtrs
              , allObjs
              , allArrs
              , computedFieldNodes
@@ -683,7 +666,7 @@ mkBaseNode subQueryReq pfxs fldAls annSelFlds selectFrom
     -- process a computed field, which returns a table
     mkComputedFieldTable (fld, jsonAggSelect, sel) =
       let prefixes = Prefixes (mkComputedFieldTableAls thisPfx fld) thisPfx
-          baseNode = annSelToBaseNode False prefixes fld sel
+          baseNode = annSelToBaseNode False prefixes fld Nothing sel
       in (fld, CFTableNode jsonAggSelect baseNode)
 
     getAnnObj (f, annFld) = case annFld of
@@ -698,27 +681,28 @@ mkBaseNode subQueryReq pfxs fldAls annSelFlds selectFrom
       FComputedField (CFSTable jas sel) -> Just (f, jas, sel)
       _                                 -> Nothing
 
-annSelToBaseNode :: Bool -> Prefixes -> FieldName -> AnnSimpleSel -> BaseNode
-annSelToBaseNode subQueryReq pfxs fldAls annSel =
-  mkBaseNode subQueryReq pfxs fldAls (TAFNodes selFlds) tabFrm tabPerm tabArgs strfyNum
+annSelToBaseNode
+  :: Bool -> Prefixes -> FieldName -> Maybe (NonEmpty PGCol) -> AnnSimpleSel -> BaseNode
+annSelToBaseNode subQueryReq pfxs fldAls pkeyCols annSel =
+  mkBaseNode subQueryReq pfxs fldAls (TAFNodes selFlds) tabFrm tabPerm tabArgs pkeyCols strfyNum
   where
     AnnSelG selFlds tabFrm tabPerm tabArgs strfyNum = annSel
 
 mkObjNode :: Prefixes -> (FieldName, ObjSel) -> ObjNode
 mkObjNode pfxs (fldName, AnnRelG _ rMapn rAnnSel) =
-  ObjNode rMapn $ annSelToBaseNode False pfxs fldName rAnnSel
+  ObjNode rMapn $ annSelToBaseNode False pfxs fldName Nothing rAnnSel
 
 mkArrNode :: Bool -> Prefixes -> (FieldName, ArrSel) -> ArrNode
 mkArrNode subQueryReq pfxs (fldName, annArrSel) = case annArrSel of
   ASSimple annArrRel ->
-    let bn = annSelToBaseNode subQueryReq pfxs fldName $ aarAnnSel annArrRel
+    let bn = annSelToBaseNode subQueryReq pfxs fldName Nothing $ aarAnnSel annArrRel
         permLimit = getPermLimit $ aarAnnSel annArrRel
         extr = asJsonAggExtr JASMultipleRows (S.toAlias fldName) subQueryReq permLimit $
                _bnOrderBy bn
     in ArrNode [extr] (aarMapping annArrRel) bn
 
   ASAgg annAggSel -> aggSelToArrNode pfxs fldName annAggSel
-  -- TODO: ASConnection connectionSel -> connectionSelToArrNode pfxs fldName connectionSel
+  ASConnection connectionSel -> connectionSelToArrNode pfxs fldName connectionSel
 
 injectJoinCond :: S.BoolExp       -- ^ Join condition
                -> S.BoolExp -- ^ Where condition
@@ -791,23 +775,12 @@ baseNodeToSel joinCond baseNode =
                 }
       in S.mkLateralFromItem sel als
 
--- mkConnectionSelect :: ConnectionSelect S.SQLExp -> S.Select
--- mkConnectionSelect annConnectionSel =
---   prefixNumToAliases $ arrNodeToSelect bn extr $ S.BELit True
---   where
---     connectionSelect = AnnRelG rootRelName HM.empty annConnectionSel
---     rootIden = Iden "root"
---     rootPrefix = Prefixes rootIden rootIden
---     ArrNode extr _ bn =
---       connectionSelToArrNode rootPrefix (FieldName "root") connectionSelect
-
 data TableSource
   = TableSource
     { _tsFrom       :: !SelectFrom
     , _tsPermission :: !TablePerm
     , _tsArgs       :: !TableArgs
-    }
-  deriving (Show, Eq, Generic)
+    } deriving (Show, Eq, Generic)
 instance Hashable TableSource
 
 
@@ -825,8 +798,8 @@ instance Hashable TableSource
 
 data BuildState
   = BuildState
-    { _bsAliasGenerator  :: !Int
-    , _bsJoinTree        :: !JoinTree
+    { _bsAliasGenerator :: !Int
+    , _bsJoinTree       :: !JoinTree
     }
 
 type Build = State BuildState
@@ -923,6 +896,72 @@ mkSQLSelect jsonAggSelect annSel =
             $ _bnOrderBy baseNode
     rootFldIden = toIden rootFldName
     rootPrefix = Prefixes rootFldIden rootFldIden
-    baseNode = annSelToBaseNode False rootPrefix rootFldName annSel
+    baseNode = annSelToBaseNode False rootPrefix rootFldName Nothing annSel
     rootFldName = FieldName "root"
     rootFldAls  = S.Alias $ toIden rootFldName
+
+mkConnectionSelectNodeAndExtr
+  :: Prefixes
+  -> FieldName
+  -> Maybe (NonEmpty PGCol)
+  -> ConnectionSelect S.SQLExp
+  -> (BaseNode, S.Extractor)
+mkConnectionSelectNodeAndExtr pfxs fieldAlias primaryKeyColumns connectionSelect =
+  (baseNode, extractor)
+  where
+    AnnSelG fields selFrom perm args strfyNum = connectionSelect
+    fieldIden = toIden fieldAlias
+    mkSimpleJsonAgg rowExp ob =
+      let jsonAggExp = S.SEFnApp "json_agg" [rowExp] ob
+      in S.SEFnApp "coalesce" [jsonAggExp, S.SELit "[]"] Nothing
+
+    baseNode = foldr mergeBaseNodes (mkEmptyBaseNode fieldIden selFrom) nodeList
+    encodeBase64 t = S.SEFnApp "encode" [S.SETyAnn t $ S.TypeAnn "bytea", S.SELit "base64"] Nothing
+
+    extractor = S.Extractor extractorExp $ Just $ S.Alias fieldIden
+    (extractorExp, nodeList) = runWriter $
+      fmap (S.applyJsonBuildObj . concat) $ forM fields $
+        \(FieldName fieldText, field) -> (S.SELit fieldText:) . pure <$>
+        case field of
+          ConnectionTypename t -> pure $ S.SELit t
+          ConnectionPageInfo f -> pure $ processPageInfoFields f
+          ConnectionEdges edges ->
+            -- TODO:- Add order by here
+            fmap (flip mkSimpleJsonAgg Nothing . S.applyJsonBuildObj . concat) $ forM edges $
+            \(FieldName edgeText, edge) -> (S.SELit edgeText:) . pure <$>
+            case edge of
+              EdgeTypename t -> pure $ S.SELit t
+              EdgeCursor     -> pure $ encodeBase64 $ S.SEIden (toIden cursorAlias)
+              EdgeNode annFields -> do
+                let rootFieldName = FieldName $ "root." <> fieldText <> "." <> edgeText
+                    rootFieldIden = toIden rootFieldName
+                    edgeBaseNode = annSelToBaseNode False pfxs rootFieldName primaryKeyColumns $
+                                   AnnSelG annFields selFrom perm args strfyNum
+                tell [edgeBaseNode]
+                pure $ S.SEIden rootFieldIden
+
+    processPageInfoFields infoFields =
+      S.applyJsonBuildObj $ flip concatMap infoFields $
+      \(FieldName fieldText, field) -> S.SELit fieldText: case field of
+        PageInfoTypename t      -> pure $ S.SELit t
+        PageInfoHasNextPage     -> pure $ S.SEBool $ S.BELit True
+        PageInfoHasPreviousPage -> pure $ S.SEBool $ S.BELit False
+        PageInfoStartCursor     -> pure $ S.SELit "start cursor"
+        PageInfoEndCursor       -> pure $ S.SELit "end cursor"
+
+connectionSelToArrNode
+  :: Prefixes -> FieldName -> ArrRelConnection S.SQLExp -> ArrNode
+connectionSelToArrNode pfxs als arrRelConnSel =
+  -- TODO:- Get primary key context here.
+  let (baseNode, extr) = mkConnectionSelectNodeAndExtr pfxs als Nothing connSel
+  in ArrNode [extr] colMapping baseNode
+  where
+    AnnRelG _ colMapping connSel = arrRelConnSel
+
+mkConnectionSelect :: Maybe (NonEmpty PGCol) -> ConnectionSelect S.SQLExp -> S.Select
+mkConnectionSelect primaryKeyColumns connectionSelect =
+  let rootFieldName = FieldName "root"
+      rootIden = toIden rootFieldName
+      prefixes = Prefixes rootIden rootIden
+      (baseNode, extractor) = mkConnectionSelectNodeAndExtr prefixes rootFieldName primaryKeyColumns connectionSelect
+  in prefixNumToAliases $ arrNodeToSelect baseNode [extractor] $ S.BELit True
diff --git a/server/src-lib/Hasura/RQL/DML/Select/Types.hs b/server/src-lib/Hasura/RQL/DML/Select/Types.hs
index a078eb0f814e9..759e1d6b8b201 100644
--- a/server/src-lib/Hasura/RQL/DML/Select/Types.hs
+++ b/server/src-lib/Hasura/RQL/DML/Select/Types.hs
@@ -274,8 +274,8 @@ traverseEdgeField
   :: (Applicative f)
   => (a -> f b) -> EdgeField a -> f (EdgeField b)
 traverseEdgeField f = \case
-  EdgeTypename t -> pure $ EdgeTypename t
-  EdgeCursor -> pure EdgeCursor
+  EdgeTypename t  -> pure $ EdgeTypename t
+  EdgeCursor      -> pure EdgeCursor
   EdgeNode fields -> EdgeNode <$> traverseAnnFlds f fields
 
 data ConnectionField v
diff --git a/server/src-lib/Hasura/RQL/Types/Common.hs b/server/src-lib/Hasura/RQL/Types/Common.hs
index 27cf5f06da93c..9c70b544826b7 100644
--- a/server/src-lib/Hasura/RQL/Types/Common.hs
+++ b/server/src-lib/Hasura/RQL/Types/Common.hs
@@ -44,7 +44,7 @@ import           Data.Aeson
 import           Data.Aeson.Casing
 import           Data.Aeson.TH
 import           Instances.TH.Lift             ()
-import           Language.Haskell.TH.Syntax    (Q, TExp, Lift)
+import           Language.Haskell.TH.Syntax    (Lift, Q, TExp)
 
 import qualified Data.HashMap.Strict           as HM
 import qualified Data.Text                     as T
@@ -212,7 +212,7 @@ data PrimaryKey a
   = PrimaryKey
   { _pkConstraint :: !Constraint
   , _pkColumns    :: !(NonEmpty a)
-  } deriving (Show, Eq, Generic)
+  } deriving (Show, Eq, Generic, Foldable)
 instance (NFData a) => NFData (PrimaryKey a)
 instance (Cacheable a) => Cacheable (PrimaryKey a)
 $(makeLenses ''PrimaryKey)

From e257138fe9feb8dfd45e096c4514432c7d99ef92 Mon Sep 17 00:00:00 2001
From: Vamshi Surabhi <vamshi@hasura.io>
Date: Fri, 8 May 2020 12:22:40 +0530
Subject: [PATCH 04/29] validation support for unions and interfaces

---
 server/cabal.project.freeze                   |  10 +-
 server/graphql-engine.cabal                   |   4 +-
 .../Data/HashMap/Strict/InsOrd/Extended.hs    |   8 +-
 server/src-lib/Data/Sequence/NonEmpty.hs      |  21 +-
 server/src-lib/Hasura/GraphQL/NormalForm.hs   | 229 +++++++
 .../Hasura/GraphQL/Resolve/Introspect.hs      |   6 +-
 server/src-lib/Hasura/GraphQL/Validate.hs     |   8 +-
 .../Hasura/GraphQL/Validate/Context.hs        |  19 +-
 .../src-lib/Hasura/GraphQL/Validate/Field.hs  | 350 -----------
 .../Hasura/GraphQL/Validate/SelectionSet.hs   | 578 ++++++++++++++++++
 .../src-lib/Hasura/GraphQL/Validate/Types.hs  | 163 +++--
 11 files changed, 926 insertions(+), 470 deletions(-)
 create mode 100644 server/src-lib/Hasura/GraphQL/NormalForm.hs
 delete mode 100644 server/src-lib/Hasura/GraphQL/Validate/Field.hs
 create mode 100644 server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs

diff --git a/server/cabal.project.freeze b/server/cabal.project.freeze
index ecb9bd7c433f7..b010902930266 100644
--- a/server/cabal.project.freeze
+++ b/server/cabal.project.freeze
@@ -54,7 +54,7 @@ constraints: any.Cabal ==2.4.0.1,
              any.bytestring ==0.10.8.2,
              any.bytestring-builder ==0.10.8.2.0,
              bytestring-builder +bytestring_has_builder,
-             any.bytestring-strict-builder ==0.4.5.1,
+             any.bytestring-strict-builder ==0.4.5.3,
              any.bytestring-tree-builder ==0.2.7.2,
              any.cabal-doctest ==1.0.8,
              any.call-stack ==0.1.0,
@@ -106,7 +106,7 @@ constraints: any.Cabal ==2.4.0.1,
              any.data-serializer ==0.3.4,
              any.data-textual ==0.3.0.2,
              any.deepseq ==1.4.4.0,
-             any.deferred-folds ==0.9.10,
+             any.deferred-folds ==0.9.10.1,
              any.dense-linear-algebra ==0.1.0.0,
              any.dependent-map ==0.2.4.0,
              any.dependent-sum ==0.4,
@@ -165,7 +165,7 @@ constraints: any.Cabal ==2.4.0.1,
              http2 -devel,
              any.hvect ==0.4.0.0,
              any.immortal ==0.2.2.1,
-             any.insert-ordered-containers ==0.2.1.0,
+             any.insert-ordered-containers ==0.2.3,
              any.integer-gmp ==1.0.2.0,
              any.integer-logarithms ==1.0.3,
              integer-logarithms -check-bounds +integer-gmp,
@@ -257,7 +257,7 @@ constraints: any.Cabal ==2.4.0.1,
              scientific -bytestring-builder -integer-simple,
              any.semigroupoids ==5.3.2,
              semigroupoids +comonad +containers +contravariant +distributive +doctests +tagged +unordered-containers,
-             any.semigroups ==0.18.5,
+             any.semigroups ==0.19.1,
              semigroups +binary +bytestring -bytestring-builder +containers +deepseq +hashable +tagged +text +transformers +unordered-containers,
              any.semver ==0.3.3.1,
              any.setenv ==0.1.1.3,
@@ -280,7 +280,7 @@ constraints: any.Cabal ==2.4.0.1,
              any.template-haskell ==2.14.0.0,
              any.terminal-size ==0.3.2.1,
              any.text ==1.2.3.1,
-             any.text-builder ==0.6.5,
+             any.text-builder ==0.6.6.1,
              any.text-conversions ==0.3.0,
              any.text-latin1 ==0.3.1,
              any.text-printer ==0.5,
diff --git a/server/graphql-engine.cabal b/server/graphql-engine.cabal
index 2c821daf70bd4..ea19ff2758af8 100644
--- a/server/graphql-engine.cabal
+++ b/server/graphql-engine.cabal
@@ -196,6 +196,7 @@ library
                      , ghc-heap-view == 0.6.0
 
                      , directory
+                     , semigroups >= 0.19.1
 
   exposed-modules:     Control.Arrow.Extended
                      , Control.Arrow.Trans
@@ -338,10 +339,11 @@ library
                      , Hasura.GraphQL.Schema.Mutation.Delete
                      , Hasura.GraphQL.Schema
                      , Hasura.GraphQL.Utils
+                     , Hasura.GraphQL.NormalForm
                      , Hasura.GraphQL.Validate
                      , Hasura.GraphQL.Validate.Types
                      , Hasura.GraphQL.Validate.Context
-                     , Hasura.GraphQL.Validate.Field
+                     , Hasura.GraphQL.Validate.SelectionSet
                      , Hasura.GraphQL.Validate.InputValue
                      , Hasura.GraphQL.Explain
                      , Hasura.GraphQL.Execute
diff --git a/server/src-lib/Data/HashMap/Strict/InsOrd/Extended.hs b/server/src-lib/Data/HashMap/Strict/InsOrd/Extended.hs
index 298e88663e8e1..832b74206022d 100644
--- a/server/src-lib/Data/HashMap/Strict/InsOrd/Extended.hs
+++ b/server/src-lib/Data/HashMap/Strict/InsOrd/Extended.hs
@@ -1,14 +1,14 @@
 module Data.HashMap.Strict.InsOrd.Extended
-  ( OMap.elems
+  ( module OMap
   , groupTuples
   , groupListWith
   ) where
 
-import qualified Data.HashMap.Strict.InsOrd as OMap
+import           Data.HashMap.Strict.InsOrd as OMap
 import qualified Data.Sequence.NonEmpty     as NE
+import qualified Data.List                  as L
 
 import           Data.Hashable              (Hashable)
-import           Data.List                  (foldl')
 
 import           Prelude                    (Eq, Foldable, Functor, fmap, ($))
 
@@ -16,7 +16,7 @@ groupTuples
   :: (Eq k, Hashable k, Foldable t)
   => t (k, v) -> OMap.InsOrdHashMap k (NE.NESeq v)
 groupTuples =
-  foldl' groupFlds OMap.empty
+  L.foldl' groupFlds OMap.empty
   where
     groupFlds m (k, v) =
       OMap.insertWith (\_ c -> c NE.|> v) k (NE.init v) m
diff --git a/server/src-lib/Data/Sequence/NonEmpty.hs b/server/src-lib/Data/Sequence/NonEmpty.hs
index 6bc4548d5a512..a8f3820413f21 100644
--- a/server/src-lib/Data/Sequence/NonEmpty.hs
+++ b/server/src-lib/Data/Sequence/NonEmpty.hs
@@ -4,12 +4,14 @@ module Data.Sequence.NonEmpty
   , (|>)
   , init
   , head
+  , tail
   , toSeq
   ) where
 
-import qualified Data.Foldable as F
+import qualified Data.Foldable as Foldable
 import qualified Data.Sequence as Seq
-import           Prelude       (Eq, Show, fst, (.))
+import qualified Data.Functor  as Functor
+import           Prelude       (Eq, Show, fst, snd, (.), Semigroup(..))
 
 infixr 5 <|
 infixl 5 |>
@@ -18,8 +20,12 @@ newtype NESeq a
   = NESeq { unNESeq :: (a, Seq.Seq a)}
   deriving (Show, Eq)
 
-instance F.Foldable NESeq where
-  foldr f v = F.foldr f v . toSeq
+instance Functor.Functor NESeq where
+  fmap f (NESeq (a, rest))
+    = NESeq (f a, Functor.fmap f rest)
+
+instance Foldable.Foldable NESeq where
+  foldr f v = Foldable.foldr f v . toSeq
 
 init :: a -> NESeq a
 init a = NESeq (a, Seq.empty)
@@ -27,6 +33,9 @@ init a = NESeq (a, Seq.empty)
 head :: NESeq a -> a
 head = fst . unNESeq
 
+tail :: NESeq a -> Seq.Seq a
+tail = snd . unNESeq
+
 (|>) :: NESeq a -> a -> NESeq a
 (NESeq (h, l)) |> v = NESeq (h, l Seq.|> v)
 
@@ -35,3 +44,7 @@ v <| (NESeq (h, l)) = NESeq (v, h Seq.<| l)
 
 toSeq :: NESeq a -> Seq.Seq a
 toSeq (NESeq (v, l)) = v Seq.<| l
+
+instance Semigroup (NESeq a) where
+  (NESeq (h, l)) <> r =
+    NESeq (h, l <> toSeq r)
diff --git a/server/src-lib/Hasura/GraphQL/NormalForm.hs b/server/src-lib/Hasura/GraphQL/NormalForm.hs
new file mode 100644
index 0000000000000..af7df978c4aa3
--- /dev/null
+++ b/server/src-lib/Hasura/GraphQL/NormalForm.hs
@@ -0,0 +1,229 @@
+{-# LANGUAGE TypeFamilyDependencies #-}
+{-# LANGUAGE RecordWildCards #-}
+module Hasura.GraphQL.NormalForm
+  ( Selection(..)
+  , DenormalizedSelection
+  , DenormalizedSelectionSet
+  , DenormalizedField
+  , SelectionSet(..)
+  , ArgsMap
+  , Field(..)
+  , Typename(..)
+  , IsField(..)
+  , toField
+  , AliasedFields(..)
+  , asObjectSelectionSet
+  , ObjectSelectionSet(..)
+  , ObjectSelectionSetMap
+  , traverseObjectSelectionSet
+  , InterfaceSelectionSet
+  , getMemberSelectionSet
+  , UnionSelectionSet
+  , ScopedSelectionSet(..)
+  , emptyScopedSelectionSet
+  , getUnionSelectionSet
+  , getInterfaceSelectionSet
+  , getObjectSelectionSet
+
+  , AnnInpVal(..)
+  , AnnGValue(..)
+  , AnnGObject
+  , AnnGEnumValue(..)
+  , hasNullVal
+  , getAnnInpValKind
+  ) where
+
+import           Hasura.Prelude
+
+import qualified Data.Aeson                          as J
+import qualified Data.Aeson.Casing                   as J
+import qualified Data.Aeson.TH                       as J
+import qualified Data.HashMap.Strict                 as Map
+import qualified Data.HashMap.Strict.InsOrd.Extended as OMap
+import qualified Language.GraphQL.Draft.Syntax       as G
+
+import           Hasura.SQL.Types
+import           Hasura.SQL.Value
+import qualified Hasura.RQL.Types.Column       as RQL
+import qualified Hasura.RQL.Types.Error        as RQL
+
+data Selection f s
+  = SelectionField !G.Alias !f
+  | SelectionInlineFragmentSpread !s
+  | SelectionFragmentSpread !G.Name !s
+  deriving (Show, Eq)
+
+-- | What a processed G.SelectionSet should look like
+type family DenormalizedSelectionSet a = s | s -> a
+
+-- | What a processed G.Field should look like
+type family DenormalizedField a
+
+type DenormalizedSelection a
+  = Selection (DenormalizedField a) (DenormalizedSelectionSet a)
+
+-- | Ordered fields
+newtype AliasedFields f
+  = AliasedFields { unAliasedFields :: OMap.InsOrdHashMap G.Alias f }
+  deriving (Show, Eq, Functor, Foldable, Traversable, Semigroup)
+
+newtype ObjectSelectionSet
+  = ObjectSelectionSet { unObjectSelectionSet :: AliasedFields Field }
+  deriving (Show, Eq, Semigroup)
+
+traverseObjectSelectionSet
+  :: (Monad m) => ObjectSelectionSet -> (Field -> m a) -> m [(Text, a)]
+traverseObjectSelectionSet selectionSet f =
+  forM (OMap.toList $ unAliasedFields $ unObjectSelectionSet selectionSet) $
+    \(alias, field) -> (G.unName $ G.unAlias alias,) <$> f field
+
+type ObjectSelectionSetMap
+  = Map.HashMap G.NamedType ObjectSelectionSet
+
+data Typename = Typename
+  deriving (Show, Eq, Generic)
+
+data ScopedSelectionSet f
+  = ScopedSelectionSet
+  { _sssBaseSelectionSet    :: !(AliasedFields f)
+  -- ^ Fields that aren't explicitly defined for member types
+  , _sssMemberSelectionSets :: !ObjectSelectionSetMap
+  -- ^ SelectionSets of individual member types
+  } deriving (Show, Eq, Generic)
+
+emptyScopedSelectionSet :: ScopedSelectionSet f
+emptyScopedSelectionSet =
+  ScopedSelectionSet (AliasedFields mempty) mempty
+
+type InterfaceSelectionSet = ScopedSelectionSet Field
+
+type UnionSelectionSet = ScopedSelectionSet Typename
+
+data SelectionSet
+  = SelectionSetObject !ObjectSelectionSet
+  | SelectionSetUnion !UnionSelectionSet
+  | SelectionSetInterface !InterfaceSelectionSet
+  | SelectionSetNone
+  -- ^ in cases of enums and scalars
+  deriving (Show, Eq)
+
+getObjectSelectionSet :: SelectionSet -> Maybe ObjectSelectionSet
+getObjectSelectionSet = \case
+  SelectionSetObject s -> pure s
+  _ -> Nothing
+
+asObjectSelectionSet
+  :: (MonadError RQL.QErr m) => SelectionSet -> m ObjectSelectionSet
+asObjectSelectionSet selectionSet =
+  onNothing (getObjectSelectionSet selectionSet) $
+    RQL.throw500 "expecting ObjectSelectionSet"
+
+getUnionSelectionSet :: SelectionSet -> Maybe UnionSelectionSet
+getUnionSelectionSet = \case
+  SelectionSetUnion s -> pure s
+  _ -> Nothing
+
+getInterfaceSelectionSet :: SelectionSet -> Maybe InterfaceSelectionSet
+getInterfaceSelectionSet = \case
+  SelectionSetInterface s -> pure s
+  _ -> Nothing
+
+type ArgsMap = Map.HashMap G.Name AnnInpVal
+
+data Field
+  = Field
+  { _fName      :: !G.Name
+  , _fType      :: !G.NamedType
+  , _fArguments :: !ArgsMap
+  , _fSelSet    :: !SelectionSet
+  } deriving (Eq, Show)
+
+-- $(J.deriveToJSON (J.aesonDrop 2 J.camelCase){J.omitNothingFields=True}
+--   ''Field
+--  )
+
+-- $(J.deriveToJSON (J.aesonDrop 2 J.camelCase){J.omitNothingFields=True}
+--   ''InterfaceSelectionSet
+--  )
+
+-- $(J.deriveToJSON (J.aesonDrop 2 J.camelCase){J.omitNothingFields=True}
+--   ''SelectionSet
+--  )
+
+class IsField f where
+  getFieldName :: f -> G.Name
+  getFieldType :: f -> G.NamedType
+  getFieldArguments :: f -> ArgsMap
+  getFieldSelectionSet :: f -> SelectionSet
+
+toField :: (IsField f) => f -> Field
+toField f =
+  Field (getFieldName f) (getFieldType f)
+  (getFieldArguments f) (getFieldSelectionSet f)
+
+instance IsField Field where
+  getFieldName = _fName
+  getFieldType = _fType
+  getFieldArguments = _fArguments
+  getFieldSelectionSet = _fSelSet
+
+instance IsField Typename where
+  getFieldName _ = "__typename"
+  getFieldType _ = G.NamedType "String"
+  getFieldArguments _ = mempty
+  getFieldSelectionSet _ = SelectionSetNone
+
+getMemberSelectionSet
+  :: IsField f
+  => G.NamedType -> ScopedSelectionSet f -> ObjectSelectionSet
+getMemberSelectionSet namedType (ScopedSelectionSet {..})  =
+  fromMaybe (ObjectSelectionSet (fmap toField _sssBaseSelectionSet)) $
+  Map.lookup namedType $ _sssMemberSelectionSets
+
+data AnnInpVal
+  = AnnInpVal
+  { _aivType     :: !G.GType
+  , _aivVariable :: !(Maybe G.Variable)
+  , _aivValue    :: !AnnGValue
+  } deriving (Show, Eq)
+
+type AnnGObject = OMap.InsOrdHashMap G.Name AnnInpVal
+
+-- | See 'EnumValuesInfo' for information about what these cases mean.
+data AnnGEnumValue
+  = AGESynthetic !(Maybe G.EnumValue)
+  | AGEReference !RQL.EnumReference !(Maybe RQL.EnumValue)
+  deriving (Show, Eq)
+
+data AnnGValue
+  = AGScalar !PGScalarType !(Maybe PGScalarValue)
+  | AGEnum !G.NamedType !AnnGEnumValue
+  | AGObject !G.NamedType !(Maybe AnnGObject)
+  | AGArray !G.ListType !(Maybe [AnnInpVal])
+  deriving (Show, Eq)
+
+$(J.deriveToJSON (J.aesonDrop 4 J.camelCase){J.omitNothingFields=True}
+  ''AnnInpVal
+ )
+
+instance J.ToJSON AnnGValue where
+  -- toJSON (AGScalar ty valM) =
+  toJSON = const J.Null
+    -- J.
+    -- J.toJSON [J.toJSON ty, J.toJSON valM]
+
+hasNullVal :: AnnGValue -> Bool
+hasNullVal = \case
+  AGScalar _ Nothing                -> True
+  AGEnum _ (AGESynthetic Nothing)   -> True
+  AGEnum _ (AGEReference _ Nothing) -> True
+  AGObject _ Nothing                -> True
+  AGArray _ Nothing                 -> True
+  _                                 -> False
+
+getAnnInpValKind :: AnnGValue -> Text
+getAnnInpValKind = \case
+  AGScalar _ _ -> "scalar"
+  AGEnum _ _   -> "enum"
+  AGObject _ _ -> "object"
+  AGArray _ _  -> "array"
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Introspect.hs b/server/src-lib/Hasura/GraphQL/Resolve/Introspect.hs
index 436f7a85d52dd..4e851bacd2d3d 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Introspect.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Introspect.hs
@@ -102,9 +102,9 @@ notBuiltinFld f =
 
 getImplTypes :: (MonadReader t m, Has TypeMap t) => AsObjType -> m [ObjTyInfo]
 getImplTypes aot = do
-   tyInfo :: TypeMap <- asks getter
+   tyInfo <- asks getter
    return $ sortOn _otiName $
-     Map.elems $ getPossibleObjTypes' tyInfo aot
+     Map.elems $ getPossibleObjTypes tyInfo aot
 
 -- 4.5.2.3
 unionR
@@ -140,7 +140,7 @@ ifaceR'
   => IFaceTyInfo
   -> Field
   -> m J.Object
-ifaceR' i@(IFaceTyInfo descM n flds) fld =
+ifaceR' i@(IFaceTyInfo descM n flds implementations) fld =
   withSubFields (_fSelSet fld) $ \subFld ->
   case _fName subFld of
     "__typename"    -> retJT "__Type"
diff --git a/server/src-lib/Hasura/GraphQL/Validate.hs b/server/src-lib/Hasura/GraphQL/Validate.hs
index d39f4c5bbc168..140fd5143614c 100644
--- a/server/src-lib/Hasura/GraphQL/Validate.hs
+++ b/server/src-lib/Hasura/GraphQL/Validate.hs
@@ -137,10 +137,8 @@ validateFrag
 validateFrag (G.FragmentDefinition n onTy dirs selSet) = do
   unless (null dirs) $ throwVE
     "unexpected directives at fragment definition"
-  tyInfo <- getTyInfoVE onTy
-  objTyInfo <- onNothing (getObjTyM tyInfo) $ throwVE
-    "fragments can only be defined on object types"
-  return $ FragDef n objTyInfo selSet
+  fragmentTypeInfo <- getFragmentTyInfo onTy
+  return $ FragDef n fragmentTypeInfo selSet
 
 data RootSelSet
   = RQuery !SelSet
@@ -165,7 +163,7 @@ validateGQ (QueryParts opDef opRoot fragDefsL varValsM) = do
   -- build a validation ctx
   let valCtx = ValidationCtx (_gTypes ctx) annVarVals annFragDefs
 
-  selSet <- flip runReaderT valCtx $ denormSelSet [] opRoot $
+  selSet <- flip runReaderT valCtx $ denormalizeSelectionSet [] opRoot $
             G._todSelectionSet opDef
 
   case G._todType opDef of
diff --git a/server/src-lib/Hasura/GraphQL/Validate/Context.hs b/server/src-lib/Hasura/GraphQL/Validate/Context.hs
index b82c133812f67..a21d8e84d9924 100644
--- a/server/src-lib/Hasura/GraphQL/Validate/Context.hs
+++ b/server/src-lib/Hasura/GraphQL/Validate/Context.hs
@@ -4,6 +4,7 @@ module Hasura.GraphQL.Validate.Context
   , getInpFieldInfo
   , getTyInfo
   , getTyInfoVE
+  , getFragmentTyInfo
   , module Hasura.GraphQL.Utils
   ) where
 
@@ -19,11 +20,11 @@ import           Hasura.RQL.Types
 
 getFieldInfo
   :: ( MonadError QErr m)
-  => ObjTyInfo -> G.Name -> m ObjFldInfo
-getFieldInfo oti fldName =
-  onNothing (Map.lookup fldName $ _otiFields oti) $ throwVE $
+  => G.NamedType -> ObjFieldMap -> G.Name -> m ObjFldInfo
+getFieldInfo typeName fieldMap fldName =
+  onNothing (Map.lookup fldName fieldMap) $ throwVE $
   "field " <> showName fldName <>
-  " not found in type: " <> showNamedTy (_otiName oti)
+  " not found in type: " <> showNamedTy typeName
 
 getInpFieldInfo
   :: ( MonadError QErr m)
@@ -65,3 +66,13 @@ getTyInfoVE namedTy = do
   tyMap <- asks getter
   onNothing (Map.lookup namedTy tyMap) $
     throwVE $ "no such type exists in the schema: " <> showNamedTy namedTy
+
+getFragmentTyInfo
+  :: (MonadReader r m, Has TypeMap r, MonadError QErr m)
+  => G.NamedType -> m FragmentTypeInfo
+getFragmentTyInfo onType =
+  getTyInfoVE onType >>= \case
+    TIObj tyInfo -> pure $ FragmentTyObject tyInfo
+    TIIFace tyInfo -> pure $ FragmentTyInterface tyInfo
+    TIUnion tyInfo -> pure $ FragmentTyUnion tyInfo
+    _ -> throwVE "fragments can only be defined on object/interface/union types"
diff --git a/server/src-lib/Hasura/GraphQL/Validate/Field.hs b/server/src-lib/Hasura/GraphQL/Validate/Field.hs
deleted file mode 100644
index 46167d472f4a5..0000000000000
--- a/server/src-lib/Hasura/GraphQL/Validate/Field.hs
+++ /dev/null
@@ -1,350 +0,0 @@
-module Hasura.GraphQL.Validate.Field
-  ( ArgsMap
-  , Field(..)
-  , SelSet
-  , denormSelSet
-  ) where
-
-import           Hasura.Prelude
-
-import qualified Data.Aeson                          as J
-import qualified Data.Aeson.Casing                   as J
-import qualified Data.Aeson.TH                       as J
-import qualified Data.HashMap.Strict                 as Map
-import qualified Data.HashMap.Strict.InsOrd.Extended as OMap
-import qualified Data.List                           as L
-import qualified Data.Sequence                       as Seq
-import qualified Data.Sequence.NonEmpty              as NE
-import qualified Data.Text                           as T
-import qualified Language.GraphQL.Draft.Syntax       as G
-
-import           Hasura.GraphQL.Validate.Context
-import           Hasura.GraphQL.Validate.InputValue
-import           Hasura.GraphQL.Validate.Types
-import           Hasura.RQL.Types
-import           Hasura.SQL.Value
-
--- data ScalarInfo
---   = SIBuiltin !GBuiltin
---   | SICustom !PGScalarType
---   deriving (Show, Eq)
-
--- data GBuiltin
---   = GInt
---   | GFloat
---   | GBoolean
---   | GString
---   deriving (Show, Eq)
-
-data TypedOperation
-  = TypedOperation
-  { _toType         :: !G.OperationType
-  , _toName         :: !(Maybe G.Name)
-  , _toSelectionSet :: ![Field]
-  } deriving (Show, Eq)
-
-type ArgsMap = Map.HashMap G.Name AnnInpVal
-
-type SelSet = Seq.Seq Field
-
-data Field
-  = Field
-  { _fAlias     :: !G.Alias
-  , _fName      :: !G.Name
-  , _fType      :: !G.NamedType
-  , _fArguments :: !ArgsMap
-  , _fSelSet    :: !SelSet
-  } deriving (Eq, Show)
-
-$(J.deriveToJSON (J.aesonDrop 2 J.camelCase){J.omitNothingFields=True}
-  ''Field
- )
-
--- newtype FieldMapAlias
---   = FieldMapAlias
---   { unFieldMapAlias :: Map.HashMap G.Alias (FieldG FieldMapAlias)
---   } deriving (Show, Eq)
-
--- newtype FieldMapName
---   = FieldMapName
---   { unFieldMapName :: Map.HashMap G.Name (NE.NonEmpty (FieldG FieldMapName))
---   } deriving (Show, Eq)
-
--- type Field = FieldG FieldMapAlias
-
--- type FieldGrouped = FieldG FieldMapName
-
--- toFieldGrouped :: Field -> FieldGrouped
--- toFieldGrouped =
---   fmap groupFields
---   where
---     groupFields m =
---       FieldMapName $ groupTuples $
---       flip map (Map.elems $ unFieldMapAlias m) $ \fld ->
---       (_fName fld, toFieldGrouped fld)
-
-data FieldGroupSrc
-  = FGSFragSprd !G.Name
-  | FGSInlnFrag
-  deriving (Show, Eq)
-
-data FieldGroup
-  = FieldGroup
-  { _fgSource :: !FieldGroupSrc
-  , _fgFields :: !(Seq.Seq Field)
-  } deriving (Show, Eq)
-
--- data GLoc
---   = GLoc
---   { _glLine   :: !Int
---   , _glColumn :: !Int
---   } deriving (Show, Eq)
-
--- data GErr
---   = GErr
---   { _geMessage   :: !Text
---   , _geLocations :: ![GLoc]
---   } deriving (Show, Eq)
-
--- throwGE :: (MonadError QErr m) => Text -> m a
--- throwGE msg = throwError $ QErr msg []
-
-withDirectives
-  :: ( MonadReader ValidationCtx m
-     , MonadError QErr m
-     , MonadReusability m
-     )
-  => [G.Directive]
-  -> m a
-  -> m (Maybe a)
-withDirectives dirs act = do
-  dirDefs <- onLeft (mkMapWith G._dName dirs) $ \dups ->
-    throwVE $ "the following directives are used more than once: " <>
-    showNames dups
-
-  procDirs <- flip Map.traverseWithKey dirDefs $ \name dir ->
-    withPathK (G.unName name) $ do
-      dirInfo <- onNothing (Map.lookup (G._dName dir) defDirectivesMap) $
-                 throwVE $ "unexpected directive: " <> showName name
-      procArgs <- withPathK "args" $ processArgs (_diParams dirInfo)
-                  (G._dArguments dir)
-      getIfArg procArgs
-
-  let shouldSkip    = fromMaybe False $ Map.lookup "skip" procDirs
-      shouldInclude = fromMaybe True $ Map.lookup "include" procDirs
-
-  if not shouldSkip && shouldInclude
-    then Just <$> act
-    else return Nothing
-
-  where
-    getIfArg m = do
-      val <- onNothing (Map.lookup "if" m) $ throw500
-              "missing if argument in the directive"
-      when (isJust $ _aivVariable val) markNotReusable
-      case _aivValue val of
-        AGScalar _ (Just (PGValBoolean v)) -> return v
-        _ -> throw500 "did not find boolean scalar for if argument"
-
-denormSel
-  :: ( MonadReader ValidationCtx m
-     , MonadError QErr m
-     , MonadReusability m
-     )
-  => [G.Name] -- visited fragments
-  -> ObjTyInfo -- parent type info
-  -> G.Selection
-  -> m (Maybe (Either Field FieldGroup))
-denormSel visFrags parObjTyInfo sel = case sel of
-  G.SelectionField fld -> withPathK (G.unName $ G._fName fld) $ do
-    fldInfo <- getFieldInfo parObjTyInfo $ G._fName fld
-    fmap Left <$> denormFld visFrags fldInfo fld
-  G.SelectionFragmentSpread fragSprd ->
-    withPathK (G.unName $ G._fsName fragSprd) $
-    fmap Right <$> denormFrag visFrags parTy fragSprd
-  G.SelectionInlineFragment inlnFrag ->
-    withPathK "inlineFragment" $
-    fmap Right <$> denormInlnFrag visFrags parObjTyInfo inlnFrag
-  where
-    parTy = _otiName parObjTyInfo
-
-processArgs
-  :: ( MonadReader ValidationCtx m
-     , MonadError QErr m
-     )
-  => ParamMap
-  -> [G.Argument]
-  -> m ArgsMap
-processArgs fldParams argsL = do
-
-  args <- onLeft (mkMapWith G._aName argsL) $ \dups ->
-    throwVE $ "the following arguments are defined more than once: " <>
-    showNames dups
-
-  let requiredParams = Map.filter (G.isNotNull . _iviType) fldParams
-
-  inpArgs <- forM args $ \(G.Argument argName argVal) ->
-    withPathK (G.unName argName) $ do
-      argTy <- getArgTy argName
-      validateInputValue valueParser argTy argVal
-
-  forM_ requiredParams $ \argDef -> do
-    let param = _iviName argDef
-    onNothing (Map.lookup param inpArgs) $ throwVE $ mconcat
-      [ "the required argument ", showName param, " is missing"]
-
-  return inpArgs
-
-  where
-    getArgTy argName =
-      onNothing (_iviType <$> Map.lookup argName fldParams) $ throwVE $
-      "no such argument " <> showName argName <> " is expected"
-
-denormFld
-  :: ( MonadReader ValidationCtx m
-     , MonadError QErr m
-     , MonadReusability m
-     )
-  => [G.Name] -- visited fragments
-  -> ObjFldInfo
-  -> G.Field
-  -> m (Maybe Field)
-denormFld visFrags fldInfo (G.Field aliasM name args dirs selSet) = do
-
-  let fldTy = _fiTy fldInfo
-      fldBaseTy = getBaseTy fldTy
-
-  fldTyInfo <- getTyInfo fldBaseTy
-
-  argMap <- withPathK "args" $ processArgs (_fiParams fldInfo) args
-
-  fields <- case (fldTyInfo, selSet) of
-
-    (TIObj _, [])  ->
-      throwVE $ "field " <> showName name <> " of type "
-      <> G.showGT fldTy <> " must have a selection of subfields"
-
-    (TIObj fldObjTyInfo, _) ->
-      denormSelSet visFrags fldObjTyInfo selSet
-
-    (TIScalar _, []) -> return Seq.empty
-    (TIEnum _, []) -> return Seq.empty
-
-    (TIInpObj _, _) ->
-      throwVE $ "internal error: unexpected input type for field: "
-      <> showName name
-
-    -- when scalar/enum and no empty set
-    (_, _) ->
-      throwVE $ "field " <> showName name <> " must not have a "
-      <> "selection since type " <> G.showGT fldTy <> " has no subfields"
-
-  withPathK "directives" $ withDirectives dirs $ return $
-    Field (fromMaybe (G.Alias name) aliasM) name fldBaseTy argMap fields
-
-denormInlnFrag
-  :: ( MonadReader ValidationCtx m
-     , MonadError QErr m
-     , MonadReusability m
-     )
-  => [G.Name] -- visited fragments
-  -> ObjTyInfo -- type information of the field
-  -> G.InlineFragment
-  -> m (Maybe FieldGroup)
-denormInlnFrag visFrags fldTyInfo inlnFrag = do
-  let fldTy  = _otiName fldTyInfo
-  let fragTy = fromMaybe fldTy tyM
-  when (fldTy /= fragTy) $
-    throwVE $ "inline fragment is expected on type " <>
-    showNamedTy fldTy <> " but found " <> showNamedTy fragTy
-  withPathK "directives" $ withDirectives directives $
-    fmap (FieldGroup FGSInlnFrag) $ denormSelSet visFrags fldTyInfo selSet
-  where
-    G.InlineFragment tyM directives selSet = inlnFrag
-
-denormSelSet
-  :: ( MonadReader ValidationCtx m
-     , MonadError QErr m
-     , MonadReusability m
-     )
-  => [G.Name] -- visited fragments
-  -> ObjTyInfo
-  -> G.SelectionSet
-  -> m (Seq.Seq Field)
-denormSelSet visFrags fldTyInfo selSet =
-  withPathK "selectionSet" $ do
-    resFlds <- catMaybes <$> mapM (denormSel visFrags fldTyInfo) selSet
-    mergeFields $ foldl' flatten Seq.empty resFlds
-  where
-    flatten s (Left fld) = s Seq.|> fld
-    flatten s (Right (FieldGroup _ flds)) =
-      s Seq.>< flds
-
-mergeFields
-  :: ( MonadReader ValidationCtx m
-     , MonadError QErr m
-     , MonadReusability m
-     )
-  => Seq.Seq Field
-  -> m (Seq.Seq Field)
-mergeFields flds =
-  fmap Seq.fromList $ forM fldGroups $ \fieldGroup -> do
-    newFld <- checkMergeability fieldGroup
-    childFields <- mergeFields $ foldl' (\l f -> l Seq.>< _fSelSet f) Seq.empty
-                   $ NE.toSeq fieldGroup
-    return $ newFld {_fSelSet = childFields}
-  where
-    fldGroups = OMap.elems $ OMap.groupListWith _fAlias flds
-    -- can a group be merged?
-    checkMergeability fldGroup = do
-      let groupedFlds = toList $ NE.toSeq fldGroup
-          fldNames = L.nub $ map _fName groupedFlds
-          args = L.nub $ map _fArguments groupedFlds
-          fld = NE.head fldGroup
-          fldAl = _fAlias fld
-      when (length fldNames > 1) $
-        throwVE $ "cannot merge different fields under the same alias ("
-        <> showName (G.unAlias fldAl) <> "): "
-        <> showNames fldNames
-      when (length args > 1) $
-        throwVE $ "cannot merge fields with different arguments"
-        <> " under the same alias: "
-        <> showName (G.unAlias fldAl)
-      return fld
-
-denormFrag
-  :: ( MonadReader ValidationCtx m
-     , MonadError QErr m
-     , MonadReusability m
-     )
-  => [G.Name] -- visited fragments
-  -> G.NamedType -- parent type
-  -> G.FragmentSpread
-  -> m (Maybe FieldGroup)
-denormFrag visFrags parTy (G.FragmentSpread name directives) = do
-
-  -- check for cycles
-  when (name `elem` visFrags) $
-    throwVE $ "cannot spread fragment " <> showName name
-    <> " within itself via "
-    <> T.intercalate "," (map G.unName visFrags)
-
-  (FragDef _ fragTyInfo selSet) <- getFragInfo
-
-  let fragTy = _otiName fragTyInfo
-
-  -- we don't have unions or interfaces so we can get away with equality
-  when (fragTy /= parTy) $
-    throwVE $ "cannot spread fragment " <> showName name <> " defined on " <>
-    showNamedTy fragTy <> " when selecting fields of type " <> showNamedTy parTy
-
-  resFlds <- denormSelSet (name:visFrags) fragTyInfo selSet
-
-  withPathK "directives" $ withDirectives directives $
-    return $ FieldGroup (FGSFragSprd  name) resFlds
-
-  where
-    getFragInfo = do
-      dctx <- ask
-      onNothing (Map.lookup name $ _vcFragDefMap dctx) $
-        throwVE $ "fragment '" <> G.unName name <> "' not found"
diff --git a/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs b/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs
new file mode 100644
index 0000000000000..b653e55012c37
--- /dev/null
+++ b/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs
@@ -0,0 +1,578 @@
+{-# LANGUAGE TypeFamilyDependencies #-}
+{-# LANGUAGE RecordWildCards #-}
+module Hasura.GraphQL.Validate.SelectionSet
+  ( ArgsMap
+  , Field(..)
+  , AliasedFields(..)
+  , SelectionSet(..)
+  , ObjectSelectionSet(..)
+  , traverseObjectSelectionSet
+  , InterfaceSelectionSet
+  , UnionSelectionSet
+  -- , denormalizeSelectionSet
+  , denormalizeObjectSelectionSet
+  , asObjectSelectionSet
+  ) where
+
+import           Hasura.Prelude
+
+import qualified Data.Text                           as T
+import qualified Data.HashMap.Strict                 as Map
+import qualified Data.HashSet                        as Set
+import qualified Data.HashMap.Strict.InsOrd.Extended as OMap
+import qualified Language.GraphQL.Draft.Syntax       as G
+import qualified Data.Sequence.NonEmpty              as NE
+import qualified Data.List                           as L
+
+import           Hasura.GraphQL.Validate.Context
+import           Hasura.GraphQL.Validate.Types
+import           Hasura.GraphQL.Validate.InputValue
+import           Hasura.GraphQL.NormalForm
+import           Hasura.RQL.Types
+import           Hasura.SQL.Value
+
+class HasSelectionSet a where
+
+  getTypename :: a -> G.NamedType
+  getMemberTypes :: a -> Set.HashSet G.NamedType
+
+  denormalizeField_
+    :: ( MonadReader ValidationCtx m
+       , MonadError QErr m
+       , MonadReusability m
+       , MonadState [G.Name] m
+       )
+    => a
+    -> G.Field
+    -> m (Maybe (DenormalizedField a))
+
+  mergeSelections
+    :: ( MonadReader ValidationCtx m
+       , MonadError QErr m
+       , MonadReusability m
+       )
+    => [Selection (DenormalizedField a) (DenormalizedSelectionSet a)]
+    -> m (DenormalizedSelectionSet a)
+
+  fromObjectSelectionSet
+    :: G.NamedType
+    -- ^ parent typename
+    -> G.NamedType
+    -- ^ fragment typename
+    -> Set.HashSet G.NamedType
+    -> DenormalizedSelectionSet ObjTyInfo
+    -> DenormalizedSelectionSet a
+
+  fromInterfaceSelectionSet
+    :: G.NamedType
+    -- ^ parent typename
+    -> G.NamedType
+    -- ^ fragment typename
+    -> Set.HashSet G.NamedType
+    -> DenormalizedSelectionSet IFaceTyInfo
+    -> DenormalizedSelectionSet a
+
+  fromUnionSelectionSet
+    :: G.NamedType
+    -- ^ parent typename
+    -> G.NamedType
+    -- ^ fragment typename
+    -> Set.HashSet G.NamedType
+    -> DenormalizedSelectionSet UnionTyInfo
+    -> DenormalizedSelectionSet a
+
+denormalizeObjectSelectionSet
+  :: ( MonadError QErr m
+     , MonadReusability m
+     )
+  => ValidationCtx
+  -> ObjTyInfo
+  -> G.SelectionSet
+  -> m ObjectSelectionSet
+denormalizeObjectSelectionSet validationCtx objectTypeInfo selectionSet =
+  flip evalStateT [] $ flip runReaderT validationCtx $
+    denormalizeSelectionSet objectTypeInfo selectionSet
+
+denormalizeSelectionSet
+  :: ( MonadReader ValidationCtx m
+     , MonadError QErr m
+     , MonadReusability m
+     , HasSelectionSet a
+     , MonadState [G.Name] m
+     )
+  => a
+  -> G.SelectionSet
+  -> m (DenormalizedSelectionSet a)
+denormalizeSelectionSet fieldTypeInfo selectionSet =
+  withPathK "selectionSet" $ do
+    resolvedSelections <- catMaybes <$>
+      mapM (denormalizeSelection fieldTypeInfo) selectionSet
+    mergeSelections resolvedSelections
+
+-- | While interfaces and objects have fields, unions do not, so
+-- this is a specialized function for every Object type
+denormalizeSelection
+  :: ( MonadReader ValidationCtx m
+     , MonadError QErr m
+     , MonadReusability m
+     , MonadState [G.Name] m
+     , HasSelectionSet a
+     )
+  => a -- parent type info
+  -> G.Selection
+  -> m (Maybe (DenormalizedSelection a))
+denormalizeSelection parentTypeInfo = \case
+  G.SelectionField fld -> withPathK (G.unName $ G._fName fld) $ do
+    let fieldName = G._fName fld
+        fieldAlias = fromMaybe (G.Alias fieldName) $ G._fAlias fld
+    fmap (SelectionField fieldAlias) <$> denormalizeField_ parentTypeInfo fld
+  G.SelectionFragmentSpread (G.FragmentSpread name directives) -> do
+    FragDef _ fragmentTyInfo fragmentSelectionSet <- getFragmentInfo name
+    withPathK (G.unName name) $
+      fmap (SelectionFragmentSpread name) <$>
+      denormalizeFragment parentTypeInfo fragmentTyInfo directives fragmentSelectionSet
+  G.SelectionInlineFragment (G.InlineFragment {..}) -> do
+    let fragmentType = fromMaybe (getTypename parentTypeInfo) _ifTypeCondition
+    fragmentTyInfo <- getFragmentTyInfo fragmentType
+    withPathK "inlineFragment" $ fmap SelectionInlineFragmentSpread <$>
+      denormalizeFragment parentTypeInfo fragmentTyInfo _ifDirectives _ifSelectionSet
+
+denormalizeFragment
+  :: ( MonadReader ValidationCtx m
+     , MonadError QErr m
+     , MonadReusability m
+     , MonadState [G.Name] m
+     , HasSelectionSet a
+     )
+  => a
+  -> FragmentTypeInfo
+  -> [G.Directive]
+  -> G.SelectionSet
+  -> m (Maybe (DenormalizedSelectionSet a))
+denormalizeFragment parentTyInfo fragmentTyInfo directives fragmentSelectionSet = do
+  commonTypes <- validateSpread
+  case fragmentTyInfo of
+    FragmentTyObject objTyInfo ->
+      withDirectives directives $
+      fmap (fromObjectSelectionSet parentType fragmentType commonTypes) $
+      denormalizeSelectionSet objTyInfo fragmentSelectionSet
+    FragmentTyInterface interfaceTyInfo ->
+      withDirectives directives $
+      fmap (fromInterfaceSelectionSet parentType fragmentType commonTypes) $
+      denormalizeSelectionSet interfaceTyInfo fragmentSelectionSet
+    FragmentTyUnion unionTyInfo ->
+      withDirectives directives $
+      fmap (fromUnionSelectionSet parentType fragmentType commonTypes) $
+      denormalizeSelectionSet unionTyInfo fragmentSelectionSet
+  where
+    validateSpread = do
+      let commonTypes = parentTypeMembers `Set.intersection` fragmentTypeMembers
+      if null commonTypes then
+          -- TODO: fragment source
+          -- throwVE $ "cannot spread fragment " <> showName name <> " defined on " <>
+          throwVE $ "cannot spread fragment  defined on " <> showNamedTy fragmentType
+          <> " when selecting fields of type " <> showNamedTy parentType
+         else pure commonTypes
+
+    parentType = getTypename parentTyInfo
+    parentTypeMembers = getMemberTypes parentTyInfo
+
+    fragmentType = case fragmentTyInfo of
+      FragmentTyObject tyInfo -> getTypename tyInfo
+      FragmentTyInterface tyInfo -> getTypename tyInfo
+      FragmentTyUnion tyInfo -> getTypename tyInfo
+    fragmentTypeMembers = case fragmentTyInfo of
+      FragmentTyObject tyInfo -> getMemberTypes tyInfo
+      FragmentTyInterface tyInfo -> getMemberTypes tyInfo
+      FragmentTyUnion tyInfo -> getMemberTypes tyInfo
+
+class IsField f => MergeableField f where
+
+  checkFieldMergeability
+    :: (MonadError QErr m) => G.Alias -> NE.NESeq f -> m f
+
+instance MergeableField Field where
+
+  checkFieldMergeability alias fields = do
+    let groupedFlds = toList $ NE.toSeq fields
+        fldNames = L.nub $ map getFieldName groupedFlds
+        args = L.nub $ map getFieldArguments groupedFlds
+    when (length fldNames > 1) $
+      throwVE $ "cannot merge different fields under the same alias ("
+      <> showName (G.unAlias alias) <> "): "
+      <> showNames fldNames
+    when (length args > 1) $
+      throwVE $ "cannot merge fields with different arguments"
+      <> " under the same alias: "
+      <> showName (G.unAlias alias)
+    let fld = NE.head fields
+    mergedGroupSelectionSet <- mergeSelectionSets $ fmap _fSelSet fields
+    return $ fld { _fSelSet = mergedGroupSelectionSet }
+
+instance MergeableField Typename where
+
+  checkFieldMergeability _ fields = pure $ NE.head fields
+
+parseArguments
+  :: ( MonadReader ValidationCtx m
+     , MonadError QErr m
+     )
+  => ParamMap
+  -> [G.Argument]
+  -> m ArgsMap
+parseArguments fldParams argsL = do
+
+  args <- onLeft (mkMapWith G._aName argsL) $ \dups ->
+    throwVE $ "the following arguments are defined more than once: " <>
+    showNames dups
+
+  let requiredParams = Map.filter (G.isNotNull . _iviType) fldParams
+
+  inpArgs <- forM args $ \(G.Argument argName argVal) ->
+    withPathK (G.unName argName) $ do
+      argTy <- getArgTy argName
+      validateInputValue valueParser argTy argVal
+
+  forM_ requiredParams $ \argDef -> do
+    let param = _iviName argDef
+    onNothing (Map.lookup param inpArgs) $ throwVE $ mconcat
+      [ "the required argument ", showName param, " is missing"]
+
+  return inpArgs
+
+  where
+    getArgTy argName =
+      onNothing (_iviType <$> Map.lookup argName fldParams) $ throwVE $
+      "no such argument " <> showName argName <> " is expected"
+
+mergeFields
+  :: ( MonadError QErr m
+     , MergeableField f
+     )
+  -- => Seq.Seq Field
+  => [AliasedFields f]
+  -> m (AliasedFields f)
+mergeFields flds =
+  AliasedFields <$> OMap.traverseWithKey checkFieldMergeability groups
+  where
+    -- groups :: OMap.InsOrdHashMap G.Alias (NE.NESeq f)
+    groups = foldr (OMap.unionWith (<>)) mempty $
+             map (fmap NE.init . unAliasedFields) flds
+
+-- query q {
+--    author {
+--      id
+--    }
+--    author {
+--      name
+--    }
+-- }
+--
+-- | When we are merging two selection sets down two different trees they
+-- should be of the same type, however, as it is not enforced in the type
+-- system, an internal error is thrown when this assumption is violated
+mergeSelectionSets
+  :: (MonadError QErr m) => NE.NESeq SelectionSet -> m SelectionSet
+-- mergeSelectionSets = curry $ \case
+mergeSelectionSets selectionSets =
+  case NE.head selectionSets of
+    SelectionSetObject s ->
+      SelectionSetObject <$>
+      assertingSimilar s getObjectSelectionSet mergeObjectSelectionSets
+    SelectionSetUnion s ->
+      SelectionSetUnion <$>
+      assertingSimilar s getUnionSelectionSet mergeUnionSelectionSets
+    SelectionSetInterface s ->
+      SelectionSetInterface <$>
+      assertingSimilar s getInterfaceSelectionSet mergeInterfaceSelectionSets
+    SelectionSetNone ->
+      if all (== SelectionSetNone) $ NE.tail selectionSets
+         then pure SelectionSetNone
+         else throw500 $ "mergeSelectionSets: 'same kind' assertion failed"
+  where
+    assertingSimilar
+      :: MonadError QErr m
+      => s -> (SelectionSet -> Maybe s) -> ([s] -> m s) -> m s
+    assertingSimilar s l f = do
+      let sameSelectionSets = mapMaybe l $ toList $ NE.tail selectionSets
+      if length sameSelectionSets == length (NE.tail selectionSets)
+         then f (s:sameSelectionSets)
+         else throw500 $ "mergeSelectionSets: 'same kind' assertion failed"
+
+mergeObjectSelectionSets
+  :: (MonadError QErr m) => [ObjectSelectionSet] -> m ObjectSelectionSet
+mergeObjectSelectionSets =
+  fmap ObjectSelectionSet . mergeFields . map unObjectSelectionSet
+
+mergeObjectSelectionSetMaps
+  :: (MonadError QErr m) => [ObjectSelectionSetMap] -> m ObjectSelectionSetMap
+mergeObjectSelectionSetMaps selectionSetMaps =
+  traverse mergeObjectSelectionSets $
+    foldr (Map.unionWith (<>)) mempty $ map (fmap (:[])) selectionSetMaps
+
+appendScopedSelectionSet
+  :: (MonadError QErr m, MergeableField f)
+  => ScopedSelectionSet f -> ScopedSelectionSet f -> m (ScopedSelectionSet f)
+appendScopedSelectionSet s1 s2 =
+  ScopedSelectionSet
+  <$> mergeFields [_sssBaseSelectionSet s1, _sssBaseSelectionSet s2]
+  <*> mergeObjectSelectionSetMaps [s1MembersUnified, s2MembersUnified]
+
+  where
+    s1Base = fmap toField $ _sssBaseSelectionSet s1
+    s2Base = fmap toField $ _sssBaseSelectionSet s2
+
+    s1MembersUnified =
+      (_sssMemberSelectionSets s1)
+      <> fmap (const (ObjectSelectionSet s1Base)) (_sssMemberSelectionSets s2)
+
+    s2MembersUnified =
+      (_sssMemberSelectionSets s2)
+      <> fmap (const (ObjectSelectionSet s2Base)) (_sssMemberSelectionSets s1)
+
+mergeScopedSelectionSets
+  :: (MonadError QErr m, MergeableField f)
+  => [ScopedSelectionSet f] -> m (ScopedSelectionSet f)
+mergeScopedSelectionSets selectionSets =
+  foldM appendScopedSelectionSet emptyScopedSelectionSet selectionSets
+
+mergeInterfaceSelectionSets
+  :: (MonadError QErr m) => [InterfaceSelectionSet] -> m InterfaceSelectionSet
+mergeInterfaceSelectionSets = mergeScopedSelectionSets
+
+mergeUnionSelectionSets
+  :: (MonadError QErr m) => [UnionSelectionSet] -> m UnionSelectionSet
+mergeUnionSelectionSets = mergeScopedSelectionSets
+
+withDirectives
+  :: ( MonadReader ValidationCtx m
+     , MonadError QErr m
+     , MonadReusability m
+     )
+  => [G.Directive]
+  -> m a
+  -> m (Maybe a)
+withDirectives dirs act = withPathK "directives" $ do
+  dirDefs <- onLeft (mkMapWith G._dName dirs) $ \dups ->
+    throwVE $ "the following directives are used more than once: " <>
+    showNames dups
+
+  procDirs <- flip Map.traverseWithKey dirDefs $ \name dir ->
+    withPathK (G.unName name) $ do
+      dirInfo <- onNothing (Map.lookup (G._dName dir) defDirectivesMap) $
+                 throwVE $ "unexpected directive: " <> showName name
+      procArgs <- withPathK "args" $ parseArguments (_diParams dirInfo)
+                  (G._dArguments dir)
+      getIfArg procArgs
+
+  let shouldSkip    = fromMaybe False $ Map.lookup "skip" procDirs
+      shouldInclude = fromMaybe True $ Map.lookup "include" procDirs
+
+  if not shouldSkip && shouldInclude
+    then Just <$> act
+    else return Nothing
+
+  where
+    getIfArg m = do
+      val <- onNothing (Map.lookup "if" m) $ throw500
+              "missing if argument in the directive"
+      when (isJust $ _aivVariable val) markNotReusable
+      case _aivValue val of
+        AGScalar _ (Just (PGValBoolean v)) -> return v
+        _ -> throw500 "did not find boolean scalar for if argument"
+
+getFragmentInfo
+  :: (MonadReader ValidationCtx m, MonadError QErr m, MonadState [G.Name] m)
+  => G.Name
+  -- ^ fragment name
+  -> m FragDef
+getFragmentInfo name = do
+  -- check for cycles
+  visitedFragments <- get
+  if name `elem` visitedFragments
+    then throwVE $ "cannot spread fragment " <> showName name
+         <> " within itself via "
+         <> T.intercalate "," (map G.unName visitedFragments)
+    else put $ name:visitedFragments
+  fragInfo <- Map.lookup name <$> asks _vcFragDefMap
+  onNothing fragInfo $ throwVE $ "fragment '" <> G.unName name <> "' not found"
+
+denormalizeField
+  :: ( MonadReader ValidationCtx m
+     , MonadError QErr m
+     , MonadReusability m
+     , MonadState [G.Name] m
+     )
+  => ObjFldInfo
+  -> G.Field
+  -> m (Maybe Field)
+denormalizeField fldInfo (G.Field _ name args dirs selSet) = do
+
+  let fldTy = _fiTy fldInfo
+      fldBaseTy = getBaseTy fldTy
+
+  fldTyInfo <- getTyInfo fldBaseTy
+
+  argMap <- withPathK "args" $ parseArguments (_fiParams fldInfo) args
+
+  fields <- case (fldTyInfo, selSet) of
+
+    (TIObj _, [])  ->
+      throwVE $ "field " <> showName name <> " of type "
+      <> G.showGT fldTy <> " must have a selection of subfields"
+
+    (TIObj objTyInfo, _) ->
+      SelectionSetObject <$> denormalizeSelectionSet objTyInfo selSet
+
+    (TIIFace _, [])  ->
+      throwVE $ "field " <> showName name <> " of type "
+      <> G.showGT fldTy <> " must have a selection of subfields"
+
+    (TIIFace interfaceTyInfo, _) ->
+      SelectionSetInterface <$> denormalizeSelectionSet interfaceTyInfo selSet
+
+    (TIUnion _, [])  ->
+      throwVE $ "field " <> showName name <> " of type "
+      <> G.showGT fldTy <> " must have a selection of subfields"
+
+    (TIUnion unionTyInfo, _) ->
+      SelectionSetUnion <$> denormalizeSelectionSet unionTyInfo selSet
+
+    (TIScalar _, []) -> return SelectionSetNone
+    -- when scalar/enum and no empty set
+    (TIScalar _, _) ->
+      throwVE $ "field " <> showName name <> " must not have a "
+      <> "selection since type " <> G.showGT fldTy <> " has no subfields"
+
+    (TIEnum _, []) -> return SelectionSetNone
+    (TIEnum _, _) ->
+      throwVE $ "field " <> showName name <> " must not have a "
+      <> "selection since type " <> G.showGT fldTy <> " has no subfields"
+
+    (TIInpObj _, _) ->
+      throwVE $ "internal error: unexpected input type for field: "
+      <> showName name
+
+  withDirectives dirs $ pure $ Field  name fldBaseTy argMap fields
+
+-- inlineFragmentInObjectScope
+--   :: ( MonadReader ValidationCtx m
+--      , MonadError QErr m
+--      , MonadReusability m
+--      , MonadState [G.Name] m
+--      )
+--   => ObjTyInfo -- type information of the field
+--   -> G.InlineFragment
+--   -> m (Maybe ObjectSelectionSet)
+-- inlineFragmentInObjectScope fldTyInfo inlnFrag = do
+--   let fldTy  = _otiName fldTyInfo
+--   let fragmentType = fromMaybe fldTy tyM
+--   when (fldTy /= fragmentType) $
+--     throwVE $ "inline fragment is expected on type " <>
+--     showNamedTy fldTy <> " but found " <> showNamedTy fragmentType
+--   withDirectives directives $ denormalizeObjectSelectionSet fldTyInfo selSet
+--   where
+--     G.InlineFragment tyM directives selSet = inlnFrag
+
+type instance DenormalizedSelectionSet ObjTyInfo = ObjectSelectionSet
+type instance DenormalizedField ObjTyInfo = Field
+instance HasSelectionSet ObjTyInfo where
+
+  getTypename = _otiName
+  getMemberTypes = Set.singleton . _otiName
+
+  denormalizeField_ objTyInfo field = do
+    fieldInfo <- getFieldInfo (_otiName objTyInfo) (_otiFields objTyInfo) $ G._fName field
+    denormalizeField fieldInfo field
+
+  mergeSelections selections =
+    mergeObjectSelectionSets $ map toObjectSelectionSet selections
+    where
+      toObjectSelectionSet = \case
+        SelectionField alias fld ->
+          ObjectSelectionSet $ AliasedFields $ OMap.singleton alias fld
+        SelectionInlineFragmentSpread selectionSet -> selectionSet
+        SelectionFragmentSpread _ selectionSet -> selectionSet
+
+  fromObjectSelectionSet _ _ _ objectSelectionSet =
+    objectSelectionSet
+
+  fromInterfaceSelectionSet parentType _ _ interfaceSelectionSet =
+      getMemberSelectionSet parentType interfaceSelectionSet
+
+  fromUnionSelectionSet parentType _ _ unionSelectionSet =
+      getMemberSelectionSet parentType unionSelectionSet
+
+type instance DenormalizedSelectionSet IFaceTyInfo = InterfaceSelectionSet
+type instance DenormalizedField IFaceTyInfo = Field
+
+instance HasSelectionSet IFaceTyInfo where
+
+  getTypename = _ifName
+  -- TODO
+  getMemberTypes = _ifMemberTypes
+
+  denormalizeField_ interfaceTyInfo field = do
+    fieldInfo <- getFieldInfo (_ifName interfaceTyInfo) (_ifFields interfaceTyInfo)
+                 $ G._fName field
+    denormalizeField fieldInfo field
+
+  mergeSelections selections =
+    mergeInterfaceSelectionSets $ map toInterfaceSelectionSet selections
+    where
+      toInterfaceSelectionSet = \case
+        SelectionField alias fld ->
+          ScopedSelectionSet (AliasedFields $ OMap.singleton alias fld) mempty
+        SelectionInlineFragmentSpread selectionSet -> selectionSet
+        SelectionFragmentSpread _ selectionSet -> selectionSet
+
+  fromObjectSelectionSet _ fragmentType _ objectSelectionSet =
+    ScopedSelectionSet (AliasedFields mempty) $
+      Map.singleton fragmentType objectSelectionSet
+
+  fromInterfaceSelectionSet _ _ commonTypes interfaceSelectionSet =
+    ScopedSelectionSet (AliasedFields mempty) $
+      Map.fromList $ flip map (toList commonTypes) $
+      \commonType -> (commonType, getMemberSelectionSet commonType interfaceSelectionSet)
+
+  fromUnionSelectionSet _ _ commonTypes unionSelectionSet =
+    ScopedSelectionSet (AliasedFields mempty) $
+      Map.fromList $ flip map (toList commonTypes) $
+      \commonType -> (commonType, getMemberSelectionSet commonType unionSelectionSet)
+
+type instance DenormalizedSelectionSet UnionTyInfo = UnionSelectionSet
+type instance DenormalizedField UnionTyInfo = Typename
+
+instance HasSelectionSet UnionTyInfo where
+
+  getTypename = _utiName
+  getMemberTypes = _utiMemberTypes
+
+  denormalizeField_ unionTyInfo field = do
+    let fieldMap = Map.singleton (_fiName typenameFld) typenameFld
+    fieldInfo <- getFieldInfo (_utiName unionTyInfo) fieldMap $ G._fName field
+    fmap (const Typename) <$> denormalizeField fieldInfo field
+
+  mergeSelections selections =
+    mergeUnionSelectionSets $ map toUnionSelectionSet selections
+    where
+      toUnionSelectionSet = \case
+        SelectionField alias fld ->
+          ScopedSelectionSet (AliasedFields $ OMap.singleton alias fld) mempty
+        SelectionInlineFragmentSpread selectionSet -> selectionSet
+        SelectionFragmentSpread _ selectionSet -> selectionSet
+
+  fromObjectSelectionSet _ fragmentType _ objectSelectionSet =
+    ScopedSelectionSet (AliasedFields mempty) $
+      Map.singleton fragmentType objectSelectionSet
+
+  fromInterfaceSelectionSet _ _ commonTypes interfaceSelectionSet =
+    ScopedSelectionSet (AliasedFields mempty) $
+      Map.fromList $ flip map (toList commonTypes) $
+      \commonType -> (commonType, getMemberSelectionSet commonType interfaceSelectionSet)
+
+  fromUnionSelectionSet _ _ commonTypes unionSelectionSet =
+    ScopedSelectionSet (AliasedFields mempty) $
+      Map.fromList $ flip map (toList commonTypes) $
+      \commonType -> (commonType, getMemberSelectionSet commonType unionSelectionSet)
+
diff --git a/server/src-lib/Hasura/GraphQL/Validate/Types.hs b/server/src-lib/Hasura/GraphQL/Validate/Types.hs
index 83c7e8261867e..c7d17a6989a70 100644
--- a/server/src-lib/Hasura/GraphQL/Validate/Types.hs
+++ b/server/src-lib/Hasura/GraphQL/Validate/Types.hs
@@ -1,7 +1,9 @@
+{-# LANGUAGE GADTs #-}
 module Hasura.GraphQL.Validate.Types
   ( InpValInfo(..)
   , ParamMap
 
+  , typenameFld
   , ObjFldInfo(..)
   , mkHsraObjFldInfo
   , ObjFieldMap
@@ -20,6 +22,7 @@ module Hasura.GraphQL.Validate.Types
   , IFacesSet
   , UnionTyInfo(..)
   , FragDef(..)
+  , FragmentTypeInfo(..)
   , FragDefMap
   , AnnVarVals
   , AnnInpVal(..)
@@ -46,7 +49,7 @@ module Hasura.GraphQL.Validate.Types
   , TypeInfo(..)
   , isObjTy
   , isIFaceTy
-  , getPossibleObjTypes'
+  , getPossibleObjTypes
   , getObjTyM
   , getUnionTyM
   , mkScalarTy
@@ -54,7 +57,6 @@ module Hasura.GraphQL.Validate.Types
   , getNamedTy
   , mkTyInfoMap
   , fromTyDef
-  , fromTyDefQ
   , fromSchemaDoc
   , fromSchemaDocQ
   , TypeMap
@@ -88,7 +90,6 @@ import qualified Data.Aeson                    as J
 import qualified Data.Aeson.Casing             as J
 import qualified Data.Aeson.TH                 as J
 import qualified Data.HashMap.Strict           as Map
-import qualified Data.HashMap.Strict.InsOrd    as OMap
 import qualified Data.HashSet                  as Set
 import qualified Data.Text                     as T
 import qualified Language.GraphQL.Draft.Syntax as G
@@ -100,6 +101,7 @@ import           Control.Lens                  (makePrisms)
 import qualified Hasura.RQL.Types.Column       as RQL
 
 import           Hasura.GraphQL.Utils
+import           Hasura.GraphQL.NormalForm
 import           Hasura.RQL.Instances          ()
 import           Hasura.RQL.Types.RemoteSchema
 import           Hasura.SQL.Types
@@ -126,10 +128,11 @@ fromEnumValDef (G.EnumValueDefinition descM val _) =
 
 data EnumValuesInfo
   = EnumValuesSynthetic !(Map.HashMap G.EnumValue EnumValInfo)
-  -- ^ Values for an enum that exists only in the GraphQL schema and does not have any external
-  -- source of truth.
+  -- ^ Values for an enum that exists only in the GraphQL schema and does not
+  -- have any external source of truth.
   | EnumValuesReference !RQL.EnumReference
-  -- ^ Values for an enum that is backed by an enum table reference (see "Hasura.RQL.Schema.Enum").
+  -- ^ Values for an enum that is backed by an enum table reference (see
+  -- "Hasura.RQL.Schema.Enum").
   deriving (Show, Eq, TH.Lift)
 
 normalizeEnumValues :: EnumValuesInfo -> Map.HashMap G.EnumValue EnumValInfo
@@ -257,10 +260,11 @@ instance Semigroup ObjTyInfo where
          }
 
 mkObjTyInfo
-  :: Maybe G.Description -> G.NamedType -> IFacesSet -> ObjFieldMap -> TypeLoc -> ObjTyInfo
+  :: Maybe G.Description -> G.NamedType
+  -> IFacesSet -> ObjFieldMap -> TypeLoc -> ObjTyInfo
 mkObjTyInfo descM ty iFaces flds loc =
   ObjTyInfo descM ty iFaces $ Map.insert (_fiName newFld) newFld flds
-  where newFld = typenameFld loc
+  where newFld = typenameFld
 
 mkHsraObjTyInfo
   :: Maybe G.Description
@@ -273,15 +277,16 @@ mkHsraObjTyInfo descM ty implIFaces flds =
 
 mkIFaceTyInfo
   :: Maybe G.Description -> G.NamedType
-  -> Map.HashMap G.Name ObjFldInfo -> TypeLoc -> IFaceTyInfo
+  -> Map.HashMap G.Name ObjFldInfo -> TypeLoc -> MemberTypes -> IFaceTyInfo
 mkIFaceTyInfo descM ty flds loc =
   IFaceTyInfo descM ty $ Map.insert (_fiName newFld) newFld flds
-  where newFld = typenameFld loc
+  where
+    newFld = typenameFld
 
-typenameFld :: TypeLoc -> ObjFldInfo
-typenameFld loc =
+typenameFld :: ObjFldInfo
+typenameFld =
   ObjFldInfo (Just desc) "__typename" Map.empty
-    (G.toGT $ G.toNT $ G.NamedType "String") loc
+    (G.toGT $ G.toNT $ G.NamedType "String") TLHasuraType
   where
     desc = "The name of the current Object type at runtime"
 
@@ -293,9 +298,10 @@ fromObjTyDef (G.ObjectTypeDefinition descM n ifaces _ flds) loc =
 
 data IFaceTyInfo
   = IFaceTyInfo
-  { _ifDesc   :: !(Maybe G.Description)
-  , _ifName   :: !G.NamedType
-  , _ifFields :: !ObjFieldMap
+  { _ifDesc        :: !(Maybe G.Description)
+  , _ifName        :: !G.NamedType
+  , _ifFields      :: !ObjFieldMap
+  , _ifMemberTypes :: !MemberTypes
   } deriving (Show, Eq, TH.Lift)
 
 instance EquatableGType IFaceTyInfo where
@@ -303,19 +309,18 @@ instance EquatableGType IFaceTyInfo where
     (G.NamedType, Map.HashMap G.Name (G.Name, G.GType, ParamMap))
   getEqProps a = (,) (_ifName a) (Map.map getEqProps (_ifFields a))
 
-instance Monoid IFaceTyInfo where
-  mempty = IFaceTyInfo Nothing (G.NamedType "") Map.empty
-
 instance Semigroup IFaceTyInfo where
   objA <> objB =
     objA { _ifFields = Map.union (_ifFields objA) (_ifFields objB)
          }
 
-fromIFaceDef :: G.InterfaceTypeDefinition -> TypeLoc -> IFaceTyInfo
-fromIFaceDef (G.InterfaceTypeDefinition descM n _ flds) loc =
-  mkIFaceTyInfo descM (G.NamedType n) fldMap loc
+fromIFaceDef
+  :: InterfaceImplementations -> G.InterfaceTypeDefinition -> TypeLoc -> IFaceTyInfo
+fromIFaceDef interfaceImplementations (G.InterfaceTypeDefinition descM n _ flds) loc =
+  mkIFaceTyInfo descM (G.NamedType n) fldMap loc implementations
   where
-    fldMap =  Map.fromList [(G._fldName fld, fromFldDef fld loc) | fld <- flds]
+    fldMap = Map.fromList [(G._fldName fld, fromFldDef fld loc) | fld <- flds]
+    implementations = fromMaybe mempty $ Map.lookup (G.NamedType n) interfaceImplementations
 
 type MemberTypes = Set.HashSet G.NamedType
 
@@ -414,23 +419,23 @@ data TypeInfo
 instance J.ToJSON TypeInfo where
   toJSON _ = J.String "toJSON not implemented for TypeInfo"
 
-instance J.FromJSON TypeInfo where
-  parseJSON _ = fail "FromJSON not implemented for TypeInfo"
-
 data AsObjType
-  = AOTObj ObjTyInfo
-  | AOTIFace IFaceTyInfo
+  = AOTIFace IFaceTyInfo
   | AOTUnion UnionTyInfo
 
-getPossibleObjTypes' :: TypeMap -> AsObjType -> Map.HashMap G.NamedType ObjTyInfo
-getPossibleObjTypes' _ (AOTObj obj) = toObjMap [obj]
-getPossibleObjTypes' tyMap (AOTIFace i) = toObjMap $ mapMaybe previewImplTypeM $ Map.elems tyMap
-  where
-    previewImplTypeM = \case
-      TIObj objTyInfo -> bool Nothing (Just objTyInfo) $
-         _ifName i `elem` _otiImplIFaces objTyInfo
-      _               -> Nothing
-getPossibleObjTypes' tyMap (AOTUnion u) = toObjMap $ mapMaybe (extrObjTyInfoM tyMap) $ Set.toList $ _utiMemberTypes u
+getPossibleObjTypes :: TypeMap -> AsObjType -> Map.HashMap G.NamedType ObjTyInfo
+getPossibleObjTypes tyMap = \case
+  (AOTIFace i) ->
+    toObjMap $ mapMaybe (extrObjTyInfoM tyMap) $ Set.toList $ _ifMemberTypes i
+  (AOTUnion u) ->
+    toObjMap $ mapMaybe (extrObjTyInfoM tyMap) $ Set.toList $ _utiMemberTypes u
+  -- toObjMap $ mapMaybe previewImplTypeM $ Map.elems tyMap
+  -- where
+  --   previewImplTypeM = \case
+  --     TIObj objTyInfo -> bool Nothing (Just objTyInfo) $
+  --        _ifName i `elem` _otiImplIFaces objTyInfo
+  --     _               -> Nothing
+
 
 toObjMap :: [ObjTyInfo] -> Map.HashMap G.NamedType ObjTyInfo
 toObjMap objs = foldr (\o -> Map.insert (_otiName o) o) Map.empty objs
@@ -487,7 +492,7 @@ showSPTxt :: SchemaPath -> Text
 showSPTxt p = showSPTxt' p <> showSP p
 
 validateIFace :: MonadError Text f => IFaceTyInfo -> f ()
-validateIFace (IFaceTyInfo _ n flds) =
+validateIFace (IFaceTyInfo _ n flds _) =
   when (isFldListEmpty flds) $ throwError $ "List of fields cannot be empty for interface " <> showNamedTy n
 
 validateObj :: TypeMap -> ObjTyInfo -> Either Text ()
@@ -631,20 +636,31 @@ mkTyInfoMap :: [TypeInfo] -> TypeMap
 mkTyInfoMap tyInfos =
   Map.fromList [(getNamedTy tyInfo, tyInfo) | tyInfo <- tyInfos]
 
-fromTyDef :: G.TypeDefinition -> TypeLoc -> TypeInfo
-fromTyDef tyDef loc = case tyDef of
+fromTyDef :: InterfaceImplementations -> TypeLoc -> G.TypeDefinition -> TypeInfo
+fromTyDef interfaceImplementations loc tyDef = case tyDef of
   G.TypeDefinitionScalar t      -> TIScalar $ fromScalarTyDef t loc
   G.TypeDefinitionObject t      -> TIObj $ fromObjTyDef t loc
-  G.TypeDefinitionInterface t   -> TIIFace $ fromIFaceDef t loc
+  G.TypeDefinitionInterface t   -> TIIFace $ fromIFaceDef interfaceImplementations t loc
   G.TypeDefinitionUnion t       -> TIUnion $ fromUnionTyDef t
   G.TypeDefinitionEnum t        -> TIEnum $ fromEnumTyDef t loc
   G.TypeDefinitionInputObject t -> TIInpObj $ fromInpObjTyDef t loc
 
+type InterfaceImplementations = Map.HashMap G.NamedType MemberTypes
+
 fromSchemaDoc :: G.SchemaDocument -> TypeLoc -> Either Text TypeMap
 fromSchemaDoc (G.SchemaDocument tyDefs) loc = do
-  let tyMap = mkTyInfoMap $ map (flip fromTyDef loc) tyDefs
+  let tyMap = mkTyInfoMap $ map (fromTyDef interfaceImplementations loc) tyDefs
   validateTypeMap tyMap
   return tyMap
+  where
+    interfaceImplementations :: InterfaceImplementations
+    interfaceImplementations =
+      foldr (Map.unionWith (<>)) mempty $ flip mapMaybe tyDefs $ \case
+        G.TypeDefinitionObject objectDefinition ->
+          Just $ Map.fromList $ zip
+            (G._otdImplementsInterfaces objectDefinition)
+            (repeat $ Set.singleton $ G.NamedType $ G._otdName objectDefinition)
+        _ -> Nothing
 
 validateTypeMap :: TypeMap -> Either Text ()
 validateTypeMap tyMap =  mapM_ validateTy $ Map.elems tyMap
@@ -654,9 +670,6 @@ validateTypeMap tyMap =  mapM_ validateTy $ Map.elems tyMap
     validateTy (TIIFace i) = validateIFace i
     validateTy _           = return ()
 
-fromTyDefQ :: G.TypeDefinition -> TypeLoc -> TH.Q TH.Exp
-fromTyDefQ tyDef loc = TH.lift $ fromTyDef tyDef loc
-
 fromSchemaDocQ :: G.SchemaDocument -> TypeLoc -> TH.Q TH.Exp
 fromSchemaDocQ sd loc = case fromSchemaDoc sd loc of
   Left e      -> fail $ T.unpack e
@@ -697,63 +710,21 @@ defDirectivesMap = mapFromL _diName defaultDirectives
 data FragDef
   = FragDef
   { _fdName   :: !G.Name
-  , _fdTyInfo :: !ObjTyInfo
+  , _fdTyInfo :: !FragmentTypeInfo
   , _fdSelSet :: !G.SelectionSet
   } deriving (Show, Eq)
 
+data FragmentTypeInfo
+  = FragmentTyObject !ObjTyInfo
+  | FragmentTyInterface !IFaceTyInfo
+  | FragmentTyUnion !UnionTyInfo
+  deriving (Show, Eq)
+
 type FragDefMap = Map.HashMap G.Name FragDef
 
 type AnnVarVals =
   Map.HashMap G.Variable AnnInpVal
 
-data AnnInpVal
-  = AnnInpVal
-  { _aivType     :: !G.GType
-  , _aivVariable :: !(Maybe G.Variable)
-  , _aivValue    :: !AnnGValue
-  } deriving (Show, Eq)
-
-type AnnGObject = OMap.InsOrdHashMap G.Name AnnInpVal
-
--- | See 'EnumValuesInfo' for information about what these cases mean.
-data AnnGEnumValue
-  = AGESynthetic !(Maybe G.EnumValue)
-  | AGEReference !RQL.EnumReference !(Maybe RQL.EnumValue)
-  deriving (Show, Eq)
-
-data AnnGValue
-  = AGScalar !PGScalarType !(Maybe PGScalarValue)
-  | AGEnum !G.NamedType !AnnGEnumValue
-  | AGObject !G.NamedType !(Maybe AnnGObject)
-  | AGArray !G.ListType !(Maybe [AnnInpVal])
-  deriving (Show, Eq)
-
-$(J.deriveToJSON (J.aesonDrop 4 J.camelCase){J.omitNothingFields=True}
-  ''AnnInpVal
- )
-
-instance J.ToJSON AnnGValue where
-  -- toJSON (AGScalar ty valM) =
-  toJSON = const J.Null
-    -- J.
-    -- J.toJSON [J.toJSON ty, J.toJSON valM]
-
-hasNullVal :: AnnGValue -> Bool
-hasNullVal = \case
-  AGScalar _ Nothing                -> True
-  AGEnum _ (AGESynthetic Nothing)   -> True
-  AGEnum _ (AGEReference _ Nothing) -> True
-  AGObject _ Nothing                -> True
-  AGArray _ Nothing                 -> True
-  _                                 -> False
-
-getAnnInpValKind :: AnnGValue -> Text
-getAnnInpValKind = \case
-  AGScalar _ _ -> "scalar"
-  AGEnum _ _   -> "enum"
-  AGObject _ _ -> "object"
-  AGArray _ _  -> "array"
-
 stripTypenames :: [G.ExecutableDefinition] -> [G.ExecutableDefinition]
 stripTypenames = map filterExecDef
   where
@@ -826,6 +797,10 @@ instance (MonadReusability m) => MonadReusability (ReaderT r m) where
   recordVariableUse a b = lift $ recordVariableUse a b
   markNotReusable = lift markNotReusable
 
+instance (MonadReusability m) => MonadReusability (StateT s m) where
+  recordVariableUse a b = lift $ recordVariableUse a b
+  markNotReusable = lift markNotReusable
+
 newtype ReusabilityT m a = ReusabilityT { unReusabilityT :: StateT QueryReusability m a }
   deriving (Functor, Applicative, Monad, MonadError e, MonadReader r, MonadIO)
 

From 94153cf78610132dabf9f2dd67da039d1fa9a24c Mon Sep 17 00:00:00 2001
From: Vamshi Surabhi <vamshi@hasura.io>
Date: Fri, 8 May 2020 16:51:54 +0530
Subject: [PATCH 05/29] use the new normal form everywhere

---
 server/cabal.project                          |  4 +-
 server/src-lib/Hasura/GraphQL/Execute.hs      | 39 ++++++-----
 .../src-lib/Hasura/GraphQL/Execute/Query.hs   | 12 ++--
 server/src-lib/Hasura/GraphQL/Explain.hs      | 11 ++--
 server/src-lib/Hasura/GraphQL/NormalForm.hs   | 66 +++++++++++++++++++
 .../src-lib/Hasura/GraphQL/Resolve/Action.hs  | 17 +++--
 .../src-lib/Hasura/GraphQL/Resolve/Context.hs | 10 +--
 .../src-lib/Hasura/GraphQL/Resolve/Insert.hs  |  8 ++-
 .../Hasura/GraphQL/Resolve/Introspect.hs      | 21 +++---
 .../Hasura/GraphQL/Resolve/Mutation.hs        | 17 +++--
 .../src-lib/Hasura/GraphQL/Resolve/Select.hs  | 41 +++++++-----
 .../src-lib/Hasura/GraphQL/Transport/HTTP.hs  | 15 ++++-
 .../Hasura/GraphQL/Transport/HTTP/Protocol.hs |  2 +-
 .../Hasura/GraphQL/Transport/WebSocket.hs     |  2 +-
 server/src-lib/Hasura/GraphQL/Validate.hs     | 37 +++++------
 .../Hasura/GraphQL/Validate/SelectionSet.hs   |  1 +
 16 files changed, 197 insertions(+), 106 deletions(-)

diff --git a/server/cabal.project b/server/cabal.project
index 270808e74ac39..0191292519413 100644
--- a/server/cabal.project
+++ b/server/cabal.project
@@ -33,8 +33,8 @@ source-repository-package
 
 source-repository-package
   type: git
-  location: https://github.com/hasura/graphql-parser-hs.git
-  tag: 623ad78aa46e7ba2ef1aa58134ad6136b0a85071
+  location: https://github.com/0x777/graphql-parser-hs.git
+  tag: 4d4e91296011360a21df888020275269cf0ca193
 
 source-repository-package
   type: git
diff --git a/server/src-lib/Hasura/GraphQL/Execute.hs b/server/src-lib/Hasura/GraphQL/Execute.hs
index 6fe8fd2fd07c2..a3691bfaecf33 100644
--- a/server/src-lib/Hasura/GraphQL/Execute.hs
+++ b/server/src-lib/Hasura/GraphQL/Execute.hs
@@ -56,6 +56,7 @@ import qualified Hasura.GraphQL.Execute.Query           as EQ
 import qualified Hasura.GraphQL.Resolve                 as GR
 import qualified Hasura.GraphQL.Validate                as VQ
 import qualified Hasura.GraphQL.Validate.Types          as VT
+import qualified Hasura.GraphQL.Validate.SelectionSet   as VQ
 import qualified Hasura.Logging                         as L
 import qualified Hasura.Server.Telemetry.Counters       as Telem
 
@@ -66,7 +67,7 @@ import qualified Hasura.Server.Telemetry.Counters       as Telem
 -- intermediate passes
 data GQExecPlan a
   = GExPHasura !a
-  | GExPRemote !RemoteSchemaInfo !G.TypedOperationDefinition
+  | GExPRemote !RemoteSchemaInfo !G.TypedOperationDefinition !VQ.RootSelectionSet
   deriving (Functor, Foldable, Traversable)
 
 -- | Execution context
@@ -116,7 +117,7 @@ gatherTypeLocs gCtx nodes =
       in maybe qr (Map.union qr) mr
 
 -- This is for when the graphql query is validated
-type ExecPlanPartial = GQExecPlan (GCtx, VQ.RootSelSet)
+type ExecPlanPartial = GQExecPlan (GCtx, VQ.RootSelectionSet)
 
 getExecPlanPartial
   :: (MonadReusability m, MonadError QErr m)
@@ -145,8 +146,9 @@ getExecPlanPartial userInfo sc enableAL req = do
     VT.TLHasuraType -> do
       rootSelSet <- runReaderT (VQ.validateGQ queryParts) gCtx
       return $ GExPHasura (gCtx, rootSelSet)
-    VT.TLRemoteType _ rsi ->
-      return $ GExPRemote rsi opDef
+    VT.TLRemoteType _ rsi -> do
+      rootSelSet <- runReaderT (VQ.validateGQ queryParts) gCtx
+      return $ GExPRemote rsi opDef rootSelSet
     VT.TLCustom ->
       throw500 "unexpected custom type for top level field"
   where
@@ -217,11 +219,13 @@ getResolvedExecPlan pgExecCtx planCache userInfo sqlGenCtx
             (tx, respHeaders) <- getMutOp gCtx sqlGenCtx userInfo httpManager reqHeaders selSet
             pure $ ExOpMutation respHeaders tx
           VQ.RQuery selSet -> do
-            (queryTx, plan, genSql) <- getQueryOp gCtx sqlGenCtx userInfo queryReusability (allowQueryActionExecuter httpManager reqHeaders) selSet
+            (queryTx, plan, genSql) <- getQueryOp gCtx sqlGenCtx userInfo queryReusability
+              (allowQueryActionExecuter httpManager reqHeaders) selSet
             traverse_ (addPlanToCache . EP.RPQuery) plan
             return $ ExOpQuery queryTx (Just genSql)
-          VQ.RSubscription fld -> do
-            (lqOp, plan) <- getSubsOp pgExecCtx gCtx sqlGenCtx userInfo queryReusability (restrictActionExecuter "query actions cannot be run as a subscription") fld
+          VQ.RSubscription alias fld -> do
+            (lqOp, plan) <- getSubsOp pgExecCtx gCtx sqlGenCtx userInfo queryReusability
+              (restrictActionExecuter "query actions cannot be run as a subscription") alias fld
             traverse_ (addPlanToCache . EP.RPSubs) plan
             return $ ExOpSubs lqOp
 
@@ -265,7 +269,7 @@ getQueryOp
   -> UserInfo
   -> QueryReusability
   -> QueryActionExecuter
-  -> VQ.SelSet
+  -> VQ.ObjectSelectionSet
   -> m (LazyRespTx, Maybe EQ.ReusableQueryPlan, EQ.GeneratedSqlMap)
 getQueryOp gCtx sqlGenCtx userInfo queryReusability actionExecuter selSet =
   runE gCtx sqlGenCtx userInfo $ EQ.convertQuerySelSet queryReusability selSet actionExecuter
@@ -284,14 +288,13 @@ resolveMutSelSet
      , Has [N.Header] r
      , MonadIO m
      )
-  => VQ.SelSet
+  => VQ.ObjectSelectionSet
   -> m (LazyRespTx, N.ResponseHeaders)
 resolveMutSelSet fields = do
-  aliasedTxs <- forM (toList fields) $ \fld -> do
-    fldRespTx <- case VQ._fName fld of
+  aliasedTxs <- traverseObjectSelectionSet fields $ \fld -> do
+    case VQ._fName fld of
       "__typename" -> return (return $ encJFromJValue mutationRootNamedType, [])
       _            -> evalReusabilityT $ GR.mutFldToTx fld
-    return (G.unName $ G.unAlias $ VQ._fAlias fld, fldRespTx)
 
   -- combines all transactions into a single transaction
   return (liftTx $ toSingleTx aliasedTxs, concatMap (snd . snd) aliasedTxs)
@@ -312,7 +315,7 @@ getMutOp
   -> UserInfo
   -> HTTP.Manager
   -> [N.Header]
-  -> VQ.SelSet
+  -> VQ.ObjectSelectionSet
   -> m (LazyRespTx, N.ResponseHeaders)
 getMutOp ctx sqlGenCtx userInfo manager reqHeaders selSet =
   peelReaderT $ resolveMutSelSet selSet
@@ -344,10 +347,11 @@ getSubsOpM
      )
   => PGExecCtx
   -> QueryReusability
+  -> G.Alias
   -> VQ.Field
   -> QueryActionExecuter
   -> m (EL.LiveQueryPlan, Maybe EL.ReusableLiveQueryPlan)
-getSubsOpM pgExecCtx initialReusability fld actionExecuter =
+getSubsOpM pgExecCtx initialReusability alias fld actionExecuter =
   case VQ._fName fld of
     "__typename" ->
       throwVE "you cannot create a subscription on '__typename' field"
@@ -355,7 +359,7 @@ getSubsOpM pgExecCtx initialReusability fld actionExecuter =
       (astUnresolved, finalReusability) <- runReusabilityTWith initialReusability $
         GR.queryFldToPGAST fld actionExecuter
       let varTypes = finalReusability ^? _Reusable
-      EL.buildLiveQueryPlan pgExecCtx (VQ._fAlias fld) astUnresolved varTypes
+      EL.buildLiveQueryPlan pgExecCtx alias astUnresolved varTypes
 
 getSubsOp
   :: ( MonadError QErr m
@@ -368,10 +372,11 @@ getSubsOp
   -> UserInfo
   -> QueryReusability
   -> QueryActionExecuter
+  -> G.Alias
   -> VQ.Field
   -> m (EL.LiveQueryPlan, Maybe EL.ReusableLiveQueryPlan)
-getSubsOp pgExecCtx gCtx sqlGenCtx userInfo queryReusability actionExecuter fld =
-  runE gCtx sqlGenCtx userInfo $ getSubsOpM pgExecCtx queryReusability fld actionExecuter
+getSubsOp pgExecCtx gCtx sqlGenCtx userInfo queryReusability actionExecuter alias fld =
+  runE gCtx sqlGenCtx userInfo $ getSubsOpM pgExecCtx queryReusability alias fld actionExecuter
 
 execRemoteGQ
   :: ( HasVersion
diff --git a/server/src-lib/Hasura/GraphQL/Execute/Query.hs b/server/src-lib/Hasura/GraphQL/Execute/Query.hs
index 49098984c2e88..44be5135ce9e1 100644
--- a/server/src-lib/Hasura/GraphQL/Execute/Query.hs
+++ b/server/src-lib/Hasura/GraphQL/Execute/Query.hs
@@ -21,7 +21,7 @@ import           Data.Has
 import qualified Hasura.GraphQL.Resolve                 as R
 import qualified Hasura.GraphQL.Transport.HTTP.Protocol as GH
 import qualified Hasura.GraphQL.Validate                as GV
-import qualified Hasura.GraphQL.Validate.Field          as V
+import qualified Hasura.GraphQL.Validate.SelectionSet   as V
 import qualified Hasura.SQL.DML                         as S
 
 import           Hasura.EncJSON
@@ -191,14 +191,14 @@ convertQuerySelSet
      , MonadIO m
      )
   => QueryReusability
-  -> V.SelSet
+  -> V.ObjectSelectionSet
   -> QueryActionExecuter
   -> m (LazyRespTx, Maybe ReusableQueryPlan, GeneratedSqlMap)
-convertQuerySelSet initialReusability fields actionRunner = do
+convertQuerySelSet initialReusability selSet actionRunner = do
   usrVars <- asks (_uiSession . getter)
   (fldPlans, finalReusability) <- runReusabilityTWith initialReusability $
-    forM (toList fields) $ \fld -> do
-      fldPlan <- case V._fName fld of
+    fmap (map (\(a, b) -> (G.Alias $ G.Name a, b))) $ V.traverseObjectSelectionSet selSet $ \fld -> do
+      case V._fName fld of
         "__type"     -> fldPlanFromJ <$> R.typeR fld
         "__schema"   -> fldPlanFromJ <$> R.schemaR fld
         "__typename" -> pure $ fldPlanFromJ queryRootNamedType
@@ -207,7 +207,7 @@ convertQuerySelSet initialReusability fields actionRunner = do
           (q, PlanningSt _ vars prepped) <- flip runStateT initPlanningSt $
             R.traverseQueryRootFldAST prepareWithPlan unresolvedAst
           pure . RFPPostgres $ PGPlan (R.toPGQuery q) vars prepped
-      pure (V._fAlias fld, fldPlan)
+      -- pure (V._fAlias fld, fldPlan)
   let varTypes = finalReusability ^? _Reusable
       reusablePlan = ReusableQueryPlan <$> varTypes <*> pure fldPlans
   (tx, sql) <- mkCurPlanTx usrVars fldPlans
diff --git a/server/src-lib/Hasura/GraphQL/Explain.hs b/server/src-lib/Hasura/GraphQL/Explain.hs
index 4de22a50bf841..9d93c84cb2e15 100644
--- a/server/src-lib/Hasura/GraphQL/Explain.hs
+++ b/server/src-lib/Hasura/GraphQL/Explain.hs
@@ -27,6 +27,7 @@ import qualified Hasura.GraphQL.Execute.LiveQuery       as E
 import qualified Hasura.GraphQL.Resolve                 as RS
 import qualified Hasura.GraphQL.Transport.HTTP.Protocol as GH
 import qualified Hasura.GraphQL.Validate                as GV
+import qualified Hasura.GraphQL.Validate.SelectionSet   as GV
 import qualified Hasura.SQL.DML                         as S
 
 data GQLExplain
@@ -129,16 +130,16 @@ explainGQLQuery pgExecCtx sc sqlGenCtx enableAL actionExecuter (GQLExplain query
   (gCtx, rootSelSet) <- case execPlan of
     E.GExPHasura (gCtx, rootSelSet) ->
       return (gCtx, rootSelSet)
-    E.GExPRemote _ _  ->
+    E.GExPRemote _ _ _  ->
       throw400 InvalidParams "only hasura queries can be explained"
   case rootSelSet of
     GV.RQuery selSet ->
-      runInTx $ encJFromJValue <$> traverse (explainField userInfo gCtx sqlGenCtx actionExecuter)
-      (toList selSet)
+      runInTx $ encJFromJValue <$> GV.traverseObjectSelectionSet selSet (explainField userInfo gCtx sqlGenCtx actionExecuter)
     GV.RMutation _ ->
       throw400 InvalidParams "only queries can be explained"
-    GV.RSubscription rootField -> do
-      (plan, _) <- E.getSubsOp pgExecCtx gCtx sqlGenCtx userInfo queryReusability actionExecuter rootField
+    GV.RSubscription alias rootField -> do
+      (plan, _) <- E.getSubsOp pgExecCtx gCtx sqlGenCtx userInfo
+                     queryReusability actionExecuter alias rootField
       runInTx $ encJFromJValue <$> E.explainLiveQueryPlan plan
   where
     sessionVariables = mkSessionVariablesText $ maybe [] Map.toList userVarsRaw
diff --git a/server/src-lib/Hasura/GraphQL/NormalForm.hs b/server/src-lib/Hasura/GraphQL/NormalForm.hs
index af7df978c4aa3..c07f6319d082e 100644
--- a/server/src-lib/Hasura/GraphQL/NormalForm.hs
+++ b/server/src-lib/Hasura/GraphQL/NormalForm.hs
@@ -6,6 +6,8 @@ module Hasura.GraphQL.NormalForm
   , DenormalizedSelectionSet
   , DenormalizedField
   , SelectionSet(..)
+  , RootSelectionSet(..)
+  , toGraphQLOperation
   , ArgsMap
   , Field(..)
   , Typename(..)
@@ -31,6 +33,9 @@ module Hasura.GraphQL.NormalForm
   , AnnGEnumValue(..)
   , hasNullVal
   , getAnnInpValKind
+
+  , toGraphQLField
+  , toGraphQLSelectionSet
   ) where
 
 import           Hasura.Prelude
@@ -91,6 +96,8 @@ data ScopedSelectionSet f
   -- ^ SelectionSets of individual member types
   } deriving (Show, Eq, Generic)
 
+
+
 emptyScopedSelectionSet :: ScopedSelectionSet f
 emptyScopedSelectionSet =
   ScopedSelectionSet (AliasedFields mempty) mempty
@@ -99,6 +106,36 @@ type InterfaceSelectionSet = ScopedSelectionSet Field
 
 type UnionSelectionSet = ScopedSelectionSet Typename
 
+data RootSelectionSet
+  = RQuery !ObjectSelectionSet
+  | RMutation !ObjectSelectionSet
+  | RSubscription !G.Alias !Field
+  deriving (Show, Eq)
+
+toGraphQLOperation :: RootSelectionSet -> G.ExecutableDefinition
+toGraphQLOperation = \case
+  RQuery selectionSet ->
+    mkExecutableDefinition G.OperationTypeQuery $
+    toGraphQLSelectionSet $ SelectionSetObject selectionSet
+  RMutation selectionSet ->
+    mkExecutableDefinition G.OperationTypeQuery $
+    toGraphQLSelectionSet $ SelectionSetObject selectionSet
+  RSubscription alias field ->
+    mkExecutableDefinition G.OperationTypeSubscription $
+    toGraphQLSelectionSet $ SelectionSetObject $ ObjectSelectionSet $
+      AliasedFields $ OMap.singleton alias field
+  where
+    mkExecutableDefinition operationType selectionSet =
+      G.ExecutableDefinitionOperation $ G.OperationDefinitionTyped $
+      G.TypedOperationDefinition
+        { G._todName = Nothing -- TODO, store the name too?
+        , G._todDirectives = []
+        , G._todType = operationType
+        , G._todVariableDefinitions = []
+        , G._todSelectionSet = selectionSet
+        }
+
+
 data SelectionSet
   = SelectionSetObject !ObjectSelectionSet
   | SelectionSetUnion !UnionSelectionSet
@@ -138,6 +175,35 @@ data Field
   , _fSelSet    :: !SelectionSet
   } deriving (Eq, Show)
 
+toGraphQLField :: G.Alias -> Field -> G.Field
+toGraphQLField alias Field{..} =
+  G.Field
+    { G._fName = _fName
+    , G._fArguments = [] -- TODO
+    , G._fDirectives = []
+    , G._fAlias = Just alias
+    , G._fSelectionSet =  toGraphQLSelectionSet _fSelSet
+    }
+
+toGraphQLSelectionSet :: SelectionSet -> G.SelectionSet
+toGraphQLSelectionSet = \case
+  SelectionSetObject selectionSet -> fromSelectionSet selectionSet
+  SelectionSetInterface selectionSet -> fromScopedSelectionSet selectionSet
+  SelectionSetUnion selectionSet -> fromScopedSelectionSet selectionSet
+  SelectionSetNone -> mempty
+  where
+    fromAliasedFields :: (IsField f) => AliasedFields f -> G.SelectionSet
+    fromAliasedFields =
+      map (G.SelectionField . uncurry toGraphQLField) .
+      OMap.toList . fmap toField . unAliasedFields
+    fromSelectionSet =
+      fromAliasedFields . unObjectSelectionSet
+    toInlineSelection typeName =
+      G.SelectionInlineFragment . G.InlineFragment (Just typeName) mempty .
+      fromSelectionSet
+    fromScopedSelectionSet (ScopedSelectionSet base specific) =
+      map (uncurry toInlineSelection) (Map.toList specific) <> fromAliasedFields base
+
 -- $(J.deriveToJSON (J.aesonDrop 2 J.camelCase){J.omitNothingFields=True}
 --   ''Field
 --  )
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Action.hs b/server/src-lib/Hasura/GraphQL/Resolve/Action.hs
index 9fca24d44dac9..a4111e844abcd 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Action.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Action.hs
@@ -42,7 +42,7 @@ import           Hasura.EncJSON
 import           Hasura.GraphQL.Resolve.Context
 import           Hasura.GraphQL.Resolve.InputValue
 import           Hasura.GraphQL.Resolve.Select     (processTableSelectionSet)
-import           Hasura.GraphQL.Validate.Field
+import           Hasura.GraphQL.Validate.SelectionSet
 import           Hasura.GraphQL.Validate.Types
 import           Hasura.HTTP
 import           Hasura.RQL.DDL.Headers            (HeaderConf, makeHeadersFromConf, toHeadersConf)
@@ -166,9 +166,10 @@ resolveActionMutationSync field executionContext sessionVariables = do
                                forwardClientHeaders resolvedWebhook handlerPayload
   let webhookResponseExpression = RS.AEInput $ UVSQL $
         toTxtValue $ WithScalarType PGJSONB $ PGValJSONB $ Q.JSONB $ J.toJSON webhookRes
+  selSet <- asObjectSelectionSet $ _fSelSet field
   selectAstUnresolved <-
     processOutputSelectionSet webhookResponseExpression outputType definitionList
-    (_fType field) $ _fSelSet field
+    (_fType field) selSet
   astResolved <- RS.traverseAnnSimpleSel resolveValTxt selectAstUnresolved
   let jsonAggType = mkJsonAggSelect outputType
   return $ (,respHeaders) $ asSingleRowJsonResp (RS.selectQuerySQL jsonAggType astResolved) []
@@ -218,9 +219,10 @@ resolveActionQuery field executionContext sessionVariables httpManager reqHeader
                                forwardClientHeaders resolvedWebhook handlerPayload
   let webhookResponseExpression = RS.AEInput $ UVSQL $
         toTxtValue $ WithScalarType PGJSONB $ PGValJSONB $ Q.JSONB $ J.toJSON webhookRes
+  selSet <- asObjectSelectionSet $ _fSelSet field
   selectAstUnresolved <-
     processOutputSelectionSet webhookResponseExpression outputType definitionList
-    (_fType field) $ _fSelSet field
+    (_fType field) selSet
   return selectAstUnresolved
   where
     ActionExecutionContext actionName outputType outputFields definitionList resolvedWebhook confHeaders
@@ -293,7 +295,9 @@ resolveAsyncActionQuery userInfo selectOpCtx field = do
   actionId <- withArg (_fArguments field) "id" parseActionId
   stringifyNumerics <- stringifyNum <$> asks getter
 
-  annotatedFields <- fmap (map (first FieldName)) $ withSelSet (_fSelSet field) $ \fld ->
+  selSet <- asObjectSelectionSet $ _fSelSet field
+
+  annotatedFields <- fmap (map (first FieldName)) $ traverseObjectSelectionSet selSet $ \fld ->
     case _fName fld of
       "__typename" -> return $ RS.FExp $ G.unName $ G.unNamedType $ _fType field
       "output"     -> do
@@ -301,9 +305,10 @@ resolveAsyncActionQuery userInfo selectOpCtx field = do
         let inputTableArgument = RS.AETableRow $ Just $ Iden "response_payload"
             ActionSelectOpContext outputType definitionList = selectOpCtx
             jsonAggSelect = mkJsonAggSelect outputType
+        fldSelSet <- asObjectSelectionSet $ _fSelSet fld
         (RS.FComputedField . RS.CFSTable jsonAggSelect)
           <$> processOutputSelectionSet inputTableArgument outputType
-              definitionList (_fType fld) (_fSelSet fld)
+              definitionList (_fType fld) fldSelSet
 
       -- The metadata columns
       "id"         -> return $ mkAnnFldFromPGCol "id" PGUUID
@@ -561,7 +566,7 @@ processOutputSelectionSet
   => RS.ArgumentExp UnresolvedVal
   -> GraphQLType
   -> [(PGCol, PGScalarType)]
-  -> G.NamedType -> SelSet -> m GRS.AnnSimpleSelect
+  -> G.NamedType -> ObjectSelectionSet -> m GRS.AnnSimpleSelect
 processOutputSelectionSet tableRowInput actionOutputType definitionList fldTy flds = do
   stringifyNumerics <- stringifyNum <$> asks getter
   annotatedFields <- processTableSelectionSet fldTy flds
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Context.hs b/server/src-lib/Hasura/GraphQL/Resolve/Context.hs
index 1d1974eae4e28..0178184646e0d 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Context.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Context.hs
@@ -23,7 +23,7 @@ module Hasura.GraphQL.Resolve.Context
 
   , txtConverter
 
-  , withSelSet
+  , traverseObjectSelectionSet
   , fieldAsPath
   , resolvePGCol
   , module Hasura.GraphQL.Utils
@@ -40,7 +40,7 @@ import qualified Language.GraphQL.Draft.Syntax as G
 
 import           Hasura.GraphQL.Resolve.Types
 import           Hasura.GraphQL.Utils
-import           Hasura.GraphQL.Validate.Field
+import           Hasura.GraphQL.Validate.SelectionSet
 import           Hasura.GraphQL.Validate.Types
 import           Hasura.RQL.DML.Internal       (currentSession, sessVarFromCurrentSetting)
 import           Hasura.RQL.Types
@@ -139,12 +139,6 @@ prepareColVal (WithScalarType scalarType colVal) = do
 txtConverter :: Applicative f => AnnPGVal -> f S.SQLExp
 txtConverter (AnnPGVal _ _ scalarValue) = pure $ toTxtValue scalarValue
 
-withSelSet :: (Monad m) => SelSet -> (Field -> m a) -> m [(Text, a)]
-withSelSet selSet f =
-  forM (toList selSet) $ \fld -> do
-    res <- f fld
-    return (G.unName $ G.unAlias $ _fAlias fld, res)
-
 fieldAsPath :: (MonadError QErr m) => Field -> m a -> m a
 fieldAsPath = nameAsPath . _fName
 
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Insert.hs b/server/src-lib/Hasura/GraphQL/Resolve/Insert.hs
index 13e83c5ec5a52..2e13aee89b899 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Insert.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Insert.hs
@@ -30,7 +30,7 @@ import           Hasura.GraphQL.Resolve.Context
 import           Hasura.GraphQL.Resolve.InputValue
 import           Hasura.GraphQL.Resolve.Mutation
 import           Hasura.GraphQL.Resolve.Select
-import           Hasura.GraphQL.Validate.Field
+import           Hasura.GraphQL.Validate.SelectionSet
 import           Hasura.GraphQL.Validate.Types
 import           Hasura.RQL.DML.Insert             (insertOrUpdateCheckExpr)
 import           Hasura.RQL.DML.Internal           (convAnnBoolExpPartialSQL, convPartialSQLExp,
@@ -475,7 +475,8 @@ convertInsert
   -> Field -- the mutation field
   -> m RespTx
 convertInsert role tn fld = prefixErrPath fld $ do
-  mutOutputUnres <- RR.MOutMultirowFields <$> resolveMutationFields (_fType fld) (_fSelSet fld)
+  selSet <- asObjectSelectionSet $ _fSelSet fld
+  mutOutputUnres <- RR.MOutMultirowFields <$> resolveMutationFields (_fType fld) selSet
   mutOutputRes <- RR.traverseMutationOutput resolveValTxt mutOutputUnres
   annVals <- withArg arguments "objects" asArray
   -- if insert input objects is empty array then
@@ -510,7 +511,8 @@ convertInsertOne
   -> Field -- the mutation field
   -> m RespTx
 convertInsertOne role qt field = prefixErrPath field $ do
-  tableSelFields <- processTableSelectionSet (_fType field) $ _fSelSet field
+  selSet <- asObjectSelectionSet $ _fSelSet field
+  tableSelFields <- processTableSelectionSet (_fType field) selSet
   let mutationOutputUnresolved = RR.MOutSinglerowObject tableSelFields
   mutationOutputResolved <- RR.traverseMutationOutput resolveValTxt mutationOutputUnresolved
   annInputObj <- withArg arguments "object" asObject
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Introspect.hs b/server/src-lib/Hasura/GraphQL/Resolve/Introspect.hs
index 4e851bacd2d3d..2102f93bdd869 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Introspect.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Introspect.hs
@@ -16,7 +16,7 @@ import           Hasura.GraphQL.Context
 import           Hasura.GraphQL.Resolve.Context
 import           Hasura.GraphQL.Resolve.InputValue
 import           Hasura.GraphQL.Validate.Context
-import           Hasura.GraphQL.Validate.Field
+import           Hasura.GraphQL.Validate.SelectionSet
 import           Hasura.GraphQL.Validate.InputValue
 import           Hasura.GraphQL.Validate.Types
 import           Hasura.RQL.Types
@@ -36,14 +36,15 @@ instance J.ToJSON TypeKind where
   toJSON = J.toJSON . T.pack . drop 2 . show
 
 withSubFields
-  :: (Monad m)
-  => SelSet
+  :: (MonadError QErr m)
+  => SelectionSet
   -> (Field -> m J.Value)
   -> m J.Object
-withSubFields selSet fn =
-  fmap Map.fromList $ forM (toList selSet) $ \fld -> do
-  val <- fn fld
-  return (G.unName $ G.unAlias $ _fAlias fld, val)
+withSubFields selSet fn = do
+  objectSelectionSet <- asObjectSelectionSet selSet
+  fmap Map.fromList $ traverseObjectSelectionSet objectSelectionSet fn
+  -- val <- fn fld
+  -- return (G.unName $ G.unAlias $ _fAlias fld, val)
 
 namedTyToTxt :: G.NamedType -> Text
 namedTyToTxt = G.unName . G.unNamedType
@@ -56,7 +57,7 @@ retJT = pure . J.toJSON
 
 -- 4.5.2.1
 scalarR
-  :: (Monad m)
+  :: (MonadError QErr m)
   => ScalarTyInfo
   -> Field
   -> m J.Object
@@ -156,7 +157,7 @@ ifaceR' i@(IFaceTyInfo descM n flds implementations) fld =
 
 -- 4.5.2.5
 enumTypeR
-  :: ( Monad m )
+  :: (MonadError QErr m)
   => EnumTyInfo
   -> Field
   -> m J.Object
@@ -277,7 +278,7 @@ inputValueR fld (InpValInfo descM n defM ty) =
 
 -- 4.5.5
 enumValueR
-  :: (Monad m)
+  :: (MonadError QErr m)
   => Field -> EnumValInfo -> m J.Object
 enumValueR fld (EnumValInfo descM enumVal isDeprecated) =
   withSubFields (_fSelSet fld) $ \subFld ->
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Mutation.hs b/server/src-lib/Hasura/GraphQL/Resolve/Mutation.hs
index dec9a37783ab8..37862086bcecc 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Mutation.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Mutation.hs
@@ -33,7 +33,7 @@ import           Hasura.GraphQL.Resolve.BoolExp
 import           Hasura.GraphQL.Resolve.Context
 import           Hasura.GraphQL.Resolve.InputValue
 import           Hasura.GraphQL.Resolve.Select       (processTableSelectionSet)
-import           Hasura.GraphQL.Validate.Field
+import           Hasura.GraphQL.Validate.SelectionSet
 import           Hasura.GraphQL.Validate.Types
 import           Hasura.RQL.DML.Internal             (currentSession, sessVarFromCurrentSetting)
 import           Hasura.RQL.Types
@@ -44,13 +44,14 @@ resolveMutationFields
   :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
      , Has OrdByCtx r, Has SQLGenCtx r
      )
-  => G.NamedType -> SelSet -> m (RR.MutFldsG UnresolvedVal)
+  => G.NamedType -> ObjectSelectionSet -> m (RR.MutFldsG UnresolvedVal)
 resolveMutationFields ty selSet = fmap (map (first FieldName)) $
-  withSelSet selSet $ \fld -> case _fName fld of
+  traverseObjectSelectionSet selSet $ \fld -> case _fName fld of
     "__typename"    -> return $ RR.MExp $ G.unName $ G.unNamedType ty
     "affected_rows" -> return RR.MCount
     "returning"     -> do
-      annFlds <- processTableSelectionSet (_fType fld) $ _fSelSet fld
+      annFlds <- asObjectSelectionSet (_fSelSet fld)
+                 >>= processTableSelectionSet (_fType fld)
       annFldsResolved <- traverse
         (traverse (RS.traverseAnnFld convertPGValueToTextValue)) annFlds
       return $ RR.MRet annFldsResolved
@@ -321,8 +322,9 @@ mutationFieldsResolver
      , Has OrdByCtx r, Has SQLGenCtx r
      )
   => Field -> m (RR.MutationOutputG UnresolvedVal)
-mutationFieldsResolver field =
-  RR.MOutMultirowFields <$> resolveMutationFields (_fType field) (_fSelSet field)
+mutationFieldsResolver field = do
+  asObjectSelectionSet (_fSelSet field) >>= \selSet ->
+    RR.MOutMultirowFields <$> resolveMutationFields (_fType field) selSet
 
 tableSelectionAsMutationOutput
   :: ( MonadReusability m, MonadError QErr m
@@ -331,7 +333,8 @@ tableSelectionAsMutationOutput
      )
   => Field -> m (RR.MutationOutputG UnresolvedVal)
 tableSelectionAsMutationOutput field =
-  RR.MOutSinglerowObject <$> processTableSelectionSet (_fType field) (_fSelSet field)
+  asObjectSelectionSet (_fSelSet field) >>= \selSet ->
+  RR.MOutSinglerowObject <$> processTableSelectionSet (_fType field) selSet
 
 -- | build mutation response for empty objects
 buildEmptyMutResp :: RR.MutationOutput -> EncJSON
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Select.hs b/server/src-lib/Hasura/GraphQL/Resolve/Select.hs
index 5695b4b6fe830..7c5bcc07311f6 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Select.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Select.hs
@@ -28,7 +28,7 @@ import           Hasura.GraphQL.Resolve.BoolExp
 import           Hasura.GraphQL.Resolve.Context
 import           Hasura.GraphQL.Resolve.InputValue
 import           Hasura.GraphQL.Schema             (isAggFld)
-import           Hasura.GraphQL.Validate.Field
+import           Hasura.GraphQL.Validate.SelectionSet
 import           Hasura.GraphQL.Validate.Types
 import           Hasura.RQL.DML.Internal           (onlyPositiveInt)
 import           Hasura.RQL.Types
@@ -97,12 +97,11 @@ processTableSelectionSet
   :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
      , Has OrdByCtx r, Has SQLGenCtx r
      )
-  => G.NamedType -> SelSet -> m AnnFlds
+  => G.NamedType -> ObjectSelectionSet -> m AnnFlds
 processTableSelectionSet fldTy flds =
-  forM (toList flds) $ \fld -> do
+  fmap (map (\(a, b) -> (FieldName a, b))) $ traverseObjectSelectionSet flds $ \fld -> do
     let fldName = _fName fld
-    let rqlFldName = FieldName $ G.unName $ G.unAlias $ _fAlias fld
-    (rqlFldName,) <$> case fldName of
+    case fldName of
       "__typename" -> return $ RS.FExp $ G.unName $ G.unNamedType fldTy
       _ -> do
         fldInfo <- getFldInfo fldTy fldName
@@ -131,15 +130,18 @@ fromAggSelSet
   :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
      , Has OrdByCtx r, Has SQLGenCtx r
      )
-  => PGColGNameMap -> G.NamedType -> SelSet -> m TableAggFlds
+  => PGColGNameMap -> G.NamedType -> ObjectSelectionSet -> m TableAggFlds
 fromAggSelSet colGNameMap fldTy selSet = fmap toFields $
-  withSelSet selSet $ \f -> do
+  traverseObjectSelectionSet selSet $ \f -> do
     let fTy = _fType f
-        fSelSet = _fSelSet f
     case _fName f of
       "__typename" -> return $ RS.TAFExp $ G.unName $ G.unNamedType fldTy
-      "aggregate"  -> RS.TAFAgg <$> convertAggFld colGNameMap fTy fSelSet
-      "nodes"      -> RS.TAFNodes <$> processTableSelectionSet fTy fSelSet
+      "aggregate"  -> do
+        objSelSet <-  asObjectSelectionSet $ _fSelSet f
+        RS.TAFAgg <$> convertAggFld colGNameMap fTy objSelSet
+      "nodes"      -> do
+        objSelSet <-  asObjectSelectionSet $ _fSelSet f
+        RS.TAFNodes <$> processTableSelectionSet fTy objSelSet
       G.Name t     -> throw500 $ "unexpected field in _agg node: " <> t
 
 type TableArgs = RS.TableArgsG UnresolvedVal
@@ -187,7 +189,8 @@ fromField
   -> Field -> m AnnSimpleSelect
 fromField selFrom colGNameMap permFilter permLimitM fld = fieldAsPath fld $ do
   tableArgs <- parseTableArgs colGNameMap args
-  annFlds   <- processTableSelectionSet (_fType fld) $ _fSelSet fld
+  selSet <- asObjectSelectionSet $ _fSelSet fld
+  annFlds   <- processTableSelectionSet (_fType fld) selSet
   let unresolvedPermFltr = fmapAnnBoolExp partialSQLExpToUnresolvedVal permFilter
   let tabPerm = RS.TablePerm unresolvedPermFltr permLimitM
   strfyNum <- stringifyNum <$> asks getter
@@ -322,7 +325,8 @@ fromFieldByPKey
   -> AnnBoolExpPartialSQL -> Field -> m AnnSimpleSel
 fromFieldByPKey tn colArgMap permFilter fld = fieldAsPath fld $ do
   boolExp <- pgColValToBoolExp colArgMap $ _fArguments fld
-  annFlds <- processTableSelectionSet fldTy $ _fSelSet fld
+  selSet <- asObjectSelectionSet $ _fSelSet fld
+  annFlds <- processTableSelectionSet fldTy selSet
   let tabFrom = RS.FromTable tn
       unresolvedPermFltr = fmapAnnBoolExp partialSQLExpToUnresolvedVal
                            permFilter
@@ -384,24 +388,24 @@ toFields = map (first FieldName)
 
 convertColFlds
   :: (MonadError QErr m)
-  => PGColGNameMap -> G.NamedType -> SelSet -> m RS.ColFlds
+  => PGColGNameMap -> G.NamedType -> ObjectSelectionSet -> m RS.ColFlds
 convertColFlds colGNameMap ty selSet = fmap toFields $
-  withSelSet selSet $ \fld ->
+  traverseObjectSelectionSet selSet $ \fld ->
     case _fName fld of
       "__typename" -> return $ RS.PCFExp $ G.unName $ G.unNamedType ty
       n            -> (RS.PCFCol . pgiColumn) <$> resolvePGCol colGNameMap n
 
 convertAggFld
   :: (MonadReusability m, MonadError QErr m)
-  => PGColGNameMap -> G.NamedType -> SelSet -> m RS.AggFlds
+  => PGColGNameMap -> G.NamedType -> ObjectSelectionSet -> m RS.AggFlds
 convertAggFld colGNameMap ty selSet = fmap toFields $
-  withSelSet selSet $ \fld -> do
+  traverseObjectSelectionSet selSet $ \fld -> do
     let fType = _fType fld
-        fSelSet = _fSelSet fld
     case _fName fld of
       "__typename" -> return $ RS.AFExp $ G.unName $ G.unNamedType ty
       "count"      -> RS.AFCount <$> convertCount colGNameMap (_fArguments fld)
       n            -> do
+        fSelSet <- asObjectSelectionSet $ _fSelSet fld
         colFlds <- convertColFlds colGNameMap fType fSelSet
         unless (isAggFld n) $ throwInvalidFld n
         return $ RS.AFOp $ RS.AggOp (G.unName n) colFlds
@@ -422,7 +426,8 @@ fromAggField
   -> Field -> m AnnAggSel
 fromAggField selectFrom colGNameMap permFilter permLimit fld = fieldAsPath fld $ do
   tableArgs   <- parseTableArgs colGNameMap args
-  aggSelFlds  <- fromAggSelSet colGNameMap (_fType fld) (_fSelSet fld)
+  selSet <- asObjectSelectionSet $ _fSelSet fld
+  aggSelFlds  <- fromAggSelSet colGNameMap (_fType fld) selSet
   let unresolvedPermFltr =
         fmapAnnBoolExp partialSQLExpToUnresolvedVal permFilter
   let tabPerm = RS.TablePerm unresolvedPermFltr permLimit
diff --git a/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs b/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs
index eeae95f30bff5..c70d3d26841c9 100644
--- a/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs
+++ b/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs
@@ -8,6 +8,7 @@ import qualified Network.HTTP.Types                     as N
 
 import           Hasura.EncJSON
 import           Hasura.GraphQL.Logging
+import           Hasura.GraphQL.NormalForm
 import           Hasura.GraphQL.Transport.HTTP.Protocol
 import           Hasura.HTTP
 import           Hasura.Prelude
@@ -23,6 +24,7 @@ import qualified Hasura.Logging                         as L
 import qualified Hasura.Server.Telemetry.Counters       as Telem
 import qualified Language.GraphQL.Draft.Syntax          as G
 import qualified Network.HTTP.Types                     as HTTP
+import qualified Language.GraphQL.Draft.Printer.Text    as GP
 
 runGQ
   :: ( HasVersion
@@ -46,10 +48,17 @@ runGQ reqId userInfo reqHdrs req = do
       E.GExPHasura resolvedOp -> do
         (telemTimeIO, telemQueryType, respHdrs, resp) <- runHasuraGQ reqId req userInfo resolvedOp
         return (telemCacheHit, Telem.Local, (telemTimeIO, telemQueryType, HttpResponse resp respHdrs))
-      E.GExPRemote rsi opDef  -> do
+      E.GExPRemote rsi opDef rootSelSet -> do
         let telemQueryType | G._todType opDef == G.OperationTypeMutation = Telem.Mutation
-                            | otherwise = Telem.Query
-        (telemTimeIO, resp) <- E.execRemoteGQ reqId userInfo reqHdrs req rsi opDef
+                           | otherwise = Telem.Query
+            rewrittenQuery =
+              GQLReq { _grQuery = GQLQueryText $ GP.renderExecutableDoc $
+                                  G.ExecutableDocument $ pure $
+                                  toGraphQLOperation rootSelSet
+                     , _grVariables = Nothing
+                     , _grOperationName = Nothing
+                     }
+        (telemTimeIO, resp) <- E.execRemoteGQ reqId userInfo reqHdrs rewrittenQuery rsi opDef
         return (telemCacheHit, Telem.Remote, (telemTimeIO, telemQueryType, resp))
   let telemTimeIO = fromUnits telemTimeIO_DT
       telemTimeTot = fromUnits telemTimeTot_DT
diff --git a/server/src-lib/Hasura/GraphQL/Transport/HTTP/Protocol.hs b/server/src-lib/Hasura/GraphQL/Transport/HTTP/Protocol.hs
index c3bd1c5eaeae7..feedbc15093e3 100644
--- a/server/src-lib/Hasura/GraphQL/Transport/HTTP/Protocol.hs
+++ b/server/src-lib/Hasura/GraphQL/Transport/HTTP/Protocol.hs
@@ -4,7 +4,7 @@ module Hasura.GraphQL.Transport.HTTP.Protocol
   , GQLReqUnparsed
   , GQLReqParsed
   , toParsed
-  , GQLQueryText
+  , GQLQueryText(..)
   , GQLExecDoc(..)
   , OperationName(..)
   , VariableValues
diff --git a/server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs b/server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs
index f0f5a29cc3bf1..4492aabcdb0ee 100644
--- a/server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs
+++ b/server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs
@@ -316,7 +316,7 @@ onStart serverEnv wsConn (StartMsg opId q) = catchAndIgnore $ do
   case execPlan of
     E.GExPHasura resolvedOp ->
       runHasuraGQ timerTot telemCacheHit requestId q userInfo resolvedOp
-    E.GExPRemote rsi opDef  ->
+    E.GExPRemote rsi opDef rootSelectionSet  ->
       runRemoteGQ timerTot telemCacheHit execCtx requestId userInfo reqHdrs opDef rsi
   where
     telemTransport = Telem.HTTP
diff --git a/server/src-lib/Hasura/GraphQL/Validate.hs b/server/src-lib/Hasura/GraphQL/Validate.hs
index 140fd5143614c..2e10e4a191a2d 100644
--- a/server/src-lib/Hasura/GraphQL/Validate.hs
+++ b/server/src-lib/Hasura/GraphQL/Validate.hs
@@ -1,8 +1,8 @@
 module Hasura.GraphQL.Validate
   ( validateGQ
   , showVars
-  , RootSelSet(..)
-  , SelSet
+  , RootSelectionSet(..)
+  , SelectionSet(..)
   , Field(..)
   , getTypedOp
   , QueryParts(..)
@@ -20,14 +20,14 @@ import           Hasura.Prelude
 import           Data.Has
 
 import qualified Data.HashMap.Strict                    as Map
+import qualified Data.HashMap.Strict.InsOrd.Extended    as OMap
 import qualified Data.HashSet                           as HS
-import qualified Data.Sequence                          as Seq
 import qualified Language.GraphQL.Draft.Syntax          as G
 
 import           Hasura.GraphQL.Schema
 import           Hasura.GraphQL.Transport.HTTP.Protocol
 import           Hasura.GraphQL.Validate.Context
-import           Hasura.GraphQL.Validate.Field
+import           Hasura.GraphQL.Validate.SelectionSet
 import           Hasura.GraphQL.Validate.InputValue
 import           Hasura.GraphQL.Validate.Types
 import           Hasura.RQL.Types
@@ -140,14 +140,9 @@ validateFrag (G.FragmentDefinition n onTy dirs selSet) = do
   fragmentTypeInfo <- getFragmentTyInfo onTy
   return $ FragDef n fragmentTypeInfo selSet
 
-data RootSelSet
-  = RQuery !SelSet
-  | RMutation !SelSet
-  | RSubscription !Field
-  deriving (Show, Eq)
-
 validateGQ
-  :: (MonadError QErr m, MonadReader GCtx m, MonadReusability m) => QueryParts -> m RootSelSet
+  :: (MonadError QErr m, MonadReader GCtx m, MonadReusability m)
+  => QueryParts -> m RootSelectionSet
 validateGQ (QueryParts opDef opRoot fragDefsL varValsM) = do
   ctx <- ask
 
@@ -163,19 +158,23 @@ validateGQ (QueryParts opDef opRoot fragDefsL varValsM) = do
   -- build a validation ctx
   let valCtx = ValidationCtx (_gTypes ctx) annVarVals annFragDefs
 
-  selSet <- flip runReaderT valCtx $ denormalizeSelectionSet [] opRoot $
+  selSet <- flip runReaderT valCtx $ denormalizeObjectSelectionSet valCtx opRoot $
             G._todSelectionSet opDef
 
   case G._todType opDef of
     G.OperationTypeQuery -> return $ RQuery selSet
     G.OperationTypeMutation -> return $ RMutation selSet
-    G.OperationTypeSubscription ->
-      case Seq.viewl selSet of
-        Seq.EmptyL     -> throw500 "empty selset for subscription"
-        fld Seq.:< rst -> do
-          unless (null rst) $
-            throwVE "subscription must select only one top level field"
-          return $ RSubscription fld
+    G.OperationTypeSubscription -> do
+      -- case Seq.viewl selSet of
+      --   Seq.EmptyL     -> throw500 "empty selset for subscription"
+      --   fld Seq.:< rst -> do
+      --     unless (null rst) $
+      --       throwVE "subscription must select only one top level field"
+          -- return $ RSubscription fld
+      case OMap.toList $ unAliasedFields $ unObjectSelectionSet selSet of
+        []     -> throw500 "empty selset for subscription"
+        [(alias, field)] -> return $ RSubscription alias field
+        _ -> throwVE "subscription must select only one top level field"
 
 isQueryInAllowlist :: GQLExecDoc -> HS.HashSet GQLQuery -> Bool
 isQueryInAllowlist q = HS.member gqlQuery
diff --git a/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs b/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs
index b653e55012c37..524586bc6a430 100644
--- a/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs
+++ b/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs
@@ -9,6 +9,7 @@ module Hasura.GraphQL.Validate.SelectionSet
   , traverseObjectSelectionSet
   , InterfaceSelectionSet
   , UnionSelectionSet
+  , RootSelectionSet(..)
   -- , denormalizeSelectionSet
   , denormalizeObjectSelectionSet
   , asObjectSelectionSet

From f1955aa2859b8b7d4f5db9ebc13a363e0d0032b3 Mon Sep 17 00:00:00 2001
From: Vamshi Surabhi <vamshi@hasura.io>
Date: Fri, 8 May 2020 19:36:07 +0530
Subject: [PATCH 06/29] use 'normalize' over 'denormalize' in type names

---
 server/src-lib/Hasura/GraphQL/NormalForm.hs   |  14 +-
 server/src-lib/Hasura/GraphQL/Validate.hs     |   8 +-
 .../Hasura/GraphQL/Validate/SelectionSet.hs   | 215 ++++++++----------
 3 files changed, 108 insertions(+), 129 deletions(-)

diff --git a/server/src-lib/Hasura/GraphQL/NormalForm.hs b/server/src-lib/Hasura/GraphQL/NormalForm.hs
index c07f6319d082e..3436b2d2fd4e6 100644
--- a/server/src-lib/Hasura/GraphQL/NormalForm.hs
+++ b/server/src-lib/Hasura/GraphQL/NormalForm.hs
@@ -2,9 +2,9 @@
 {-# LANGUAGE RecordWildCards #-}
 module Hasura.GraphQL.NormalForm
   ( Selection(..)
-  , DenormalizedSelection
-  , DenormalizedSelectionSet
-  , DenormalizedField
+  , NormalizedSelection
+  , NormalizedSelectionSet
+  , NormalizedField
   , SelectionSet(..)
   , RootSelectionSet(..)
   , toGraphQLOperation
@@ -59,13 +59,13 @@ data Selection f s
   deriving (Show, Eq)
 
 -- | What a processed G.SelectionSet should look like
-type family DenormalizedSelectionSet a = s | s -> a
+type family NormalizedSelectionSet a = s | s -> a
 
 -- | What a processed G.Field should look like
-type family DenormalizedField a
+type family NormalizedField a
 
-type DenormalizedSelection a
-  = Selection (DenormalizedField a) (DenormalizedSelectionSet a)
+type NormalizedSelection a
+  = Selection (NormalizedField a) (NormalizedSelectionSet a)
 
 -- | Ordered fields
 newtype AliasedFields f
diff --git a/server/src-lib/Hasura/GraphQL/Validate.hs b/server/src-lib/Hasura/GraphQL/Validate.hs
index 2e10e4a191a2d..69c8fda11b2df 100644
--- a/server/src-lib/Hasura/GraphQL/Validate.hs
+++ b/server/src-lib/Hasura/GraphQL/Validate.hs
@@ -158,19 +158,13 @@ validateGQ (QueryParts opDef opRoot fragDefsL varValsM) = do
   -- build a validation ctx
   let valCtx = ValidationCtx (_gTypes ctx) annVarVals annFragDefs
 
-  selSet <- flip runReaderT valCtx $ denormalizeObjectSelectionSet valCtx opRoot $
+  selSet <- flip runReaderT valCtx $ parseObjectSelectionSet valCtx opRoot $
             G._todSelectionSet opDef
 
   case G._todType opDef of
     G.OperationTypeQuery -> return $ RQuery selSet
     G.OperationTypeMutation -> return $ RMutation selSet
     G.OperationTypeSubscription -> do
-      -- case Seq.viewl selSet of
-      --   Seq.EmptyL     -> throw500 "empty selset for subscription"
-      --   fld Seq.:< rst -> do
-      --     unless (null rst) $
-      --       throwVE "subscription must select only one top level field"
-          -- return $ RSubscription fld
       case OMap.toList $ unAliasedFields $ unObjectSelectionSet selSet of
         []     -> throw500 "empty selset for subscription"
         [(alias, field)] -> return $ RSubscription alias field
diff --git a/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs b/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs
index 524586bc6a430..c7831b3a2411f 100644
--- a/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs
+++ b/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs
@@ -10,8 +10,7 @@ module Hasura.GraphQL.Validate.SelectionSet
   , InterfaceSelectionSet
   , UnionSelectionSet
   , RootSelectionSet(..)
-  -- , denormalizeSelectionSet
-  , denormalizeObjectSelectionSet
+  , parseObjectSelectionSet
   , asObjectSelectionSet
   ) where
 
@@ -37,7 +36,10 @@ class HasSelectionSet a where
   getTypename :: a -> G.NamedType
   getMemberTypes :: a -> Set.HashSet G.NamedType
 
-  denormalizeField_
+  fieldToSelectionSet
+    :: G.Alias -> NormalizedField a -> NormalizedSelectionSet a
+
+  parseField_
     :: ( MonadReader ValidationCtx m
        , MonadError QErr m
        , MonadReusability m
@@ -45,15 +47,15 @@ class HasSelectionSet a where
        )
     => a
     -> G.Field
-    -> m (Maybe (DenormalizedField a))
+    -> m (Maybe (NormalizedField a))
 
-  mergeSelections
+  mergeNormalizedSelectionSets
     :: ( MonadReader ValidationCtx m
        , MonadError QErr m
        , MonadReusability m
        )
-    => [Selection (DenormalizedField a) (DenormalizedSelectionSet a)]
-    -> m (DenormalizedSelectionSet a)
+    => [NormalizedSelectionSet a]
+    -> m (NormalizedSelectionSet a)
 
   fromObjectSelectionSet
     :: G.NamedType
@@ -61,8 +63,9 @@ class HasSelectionSet a where
     -> G.NamedType
     -- ^ fragment typename
     -> Set.HashSet G.NamedType
-    -> DenormalizedSelectionSet ObjTyInfo
-    -> DenormalizedSelectionSet a
+    -- ^ common types
+    -> NormalizedSelectionSet ObjTyInfo
+    -> NormalizedSelectionSet a
 
   fromInterfaceSelectionSet
     :: G.NamedType
@@ -70,8 +73,8 @@ class HasSelectionSet a where
     -> G.NamedType
     -- ^ fragment typename
     -> Set.HashSet G.NamedType
-    -> DenormalizedSelectionSet IFaceTyInfo
-    -> DenormalizedSelectionSet a
+    -> NormalizedSelectionSet IFaceTyInfo
+    -> NormalizedSelectionSet a
 
   fromUnionSelectionSet
     :: G.NamedType
@@ -79,10 +82,11 @@ class HasSelectionSet a where
     -> G.NamedType
     -- ^ fragment typename
     -> Set.HashSet G.NamedType
-    -> DenormalizedSelectionSet UnionTyInfo
-    -> DenormalizedSelectionSet a
+    -- ^ common types
+    -> NormalizedSelectionSet UnionTyInfo
+    -> NormalizedSelectionSet a
 
-denormalizeObjectSelectionSet
+parseObjectSelectionSet
   :: ( MonadError QErr m
      , MonadReusability m
      )
@@ -90,11 +94,19 @@ denormalizeObjectSelectionSet
   -> ObjTyInfo
   -> G.SelectionSet
   -> m ObjectSelectionSet
-denormalizeObjectSelectionSet validationCtx objectTypeInfo selectionSet =
+parseObjectSelectionSet validationCtx objectTypeInfo selectionSet =
   flip evalStateT [] $ flip runReaderT validationCtx $
-    denormalizeSelectionSet objectTypeInfo selectionSet
+    parseSelectionSet objectTypeInfo selectionSet
+
+selectionToSelectionSet
+  :: HasSelectionSet a
+  => NormalizedSelection a -> NormalizedSelectionSet a
+selectionToSelectionSet = \case
+  SelectionField alias fld -> fieldToSelectionSet alias fld
+  SelectionInlineFragmentSpread selectionSet -> selectionSet
+  SelectionFragmentSpread _ selectionSet -> selectionSet
 
-denormalizeSelectionSet
+parseSelectionSet
   :: ( MonadReader ValidationCtx m
      , MonadError QErr m
      , MonadReusability m
@@ -103,16 +115,17 @@ denormalizeSelectionSet
      )
   => a
   -> G.SelectionSet
-  -> m (DenormalizedSelectionSet a)
-denormalizeSelectionSet fieldTypeInfo selectionSet =
+  -> m (NormalizedSelectionSet a)
+parseSelectionSet fieldTypeInfo selectionSet =
   withPathK "selectionSet" $ do
-    resolvedSelections <- catMaybes <$>
-      mapM (denormalizeSelection fieldTypeInfo) selectionSet
-    mergeSelections resolvedSelections
+    normalizedSelections <- catMaybes <$> mapM (parseSelection fieldTypeInfo) selectionSet
+    mergeNormalizedSelections normalizedSelections
+  where
+    mergeNormalizedSelections = mergeNormalizedSelectionSets . map selectionToSelectionSet
 
 -- | While interfaces and objects have fields, unions do not, so
 -- this is a specialized function for every Object type
-denormalizeSelection
+parseSelection
   :: ( MonadReader ValidationCtx m
      , MonadError QErr m
      , MonadReusability m
@@ -121,24 +134,24 @@ denormalizeSelection
      )
   => a -- parent type info
   -> G.Selection
-  -> m (Maybe (DenormalizedSelection a))
-denormalizeSelection parentTypeInfo = \case
+  -> m (Maybe (NormalizedSelection a))
+parseSelection parentTypeInfo = \case
   G.SelectionField fld -> withPathK (G.unName $ G._fName fld) $ do
     let fieldName = G._fName fld
         fieldAlias = fromMaybe (G.Alias fieldName) $ G._fAlias fld
-    fmap (SelectionField fieldAlias) <$> denormalizeField_ parentTypeInfo fld
+    fmap (SelectionField fieldAlias) <$> parseField_ parentTypeInfo fld
   G.SelectionFragmentSpread (G.FragmentSpread name directives) -> do
     FragDef _ fragmentTyInfo fragmentSelectionSet <- getFragmentInfo name
     withPathK (G.unName name) $
       fmap (SelectionFragmentSpread name) <$>
-      denormalizeFragment parentTypeInfo fragmentTyInfo directives fragmentSelectionSet
+      parseFragment parentTypeInfo fragmentTyInfo directives fragmentSelectionSet
   G.SelectionInlineFragment (G.InlineFragment {..}) -> do
     let fragmentType = fromMaybe (getTypename parentTypeInfo) _ifTypeCondition
     fragmentTyInfo <- getFragmentTyInfo fragmentType
     withPathK "inlineFragment" $ fmap SelectionInlineFragmentSpread <$>
-      denormalizeFragment parentTypeInfo fragmentTyInfo _ifDirectives _ifSelectionSet
+      parseFragment parentTypeInfo fragmentTyInfo _ifDirectives _ifSelectionSet
 
-denormalizeFragment
+parseFragment
   :: ( MonadReader ValidationCtx m
      , MonadError QErr m
      , MonadReusability m
@@ -149,22 +162,22 @@ denormalizeFragment
   -> FragmentTypeInfo
   -> [G.Directive]
   -> G.SelectionSet
-  -> m (Maybe (DenormalizedSelectionSet a))
-denormalizeFragment parentTyInfo fragmentTyInfo directives fragmentSelectionSet = do
+  -> m (Maybe (NormalizedSelectionSet a))
+parseFragment parentTyInfo fragmentTyInfo directives fragmentSelectionSet = do
   commonTypes <- validateSpread
   case fragmentTyInfo of
     FragmentTyObject objTyInfo ->
       withDirectives directives $
       fmap (fromObjectSelectionSet parentType fragmentType commonTypes) $
-      denormalizeSelectionSet objTyInfo fragmentSelectionSet
+      parseSelectionSet objTyInfo fragmentSelectionSet
     FragmentTyInterface interfaceTyInfo ->
       withDirectives directives $
       fmap (fromInterfaceSelectionSet parentType fragmentType commonTypes) $
-      denormalizeSelectionSet interfaceTyInfo fragmentSelectionSet
+      parseSelectionSet interfaceTyInfo fragmentSelectionSet
     FragmentTyUnion unionTyInfo ->
       withDirectives directives $
       fmap (fromUnionSelectionSet parentType fragmentType commonTypes) $
-      denormalizeSelectionSet unionTyInfo fragmentSelectionSet
+      parseSelectionSet unionTyInfo fragmentSelectionSet
   where
     validateSpread = do
       let commonTypes = parentTypeMembers `Set.intersection` fragmentTypeMembers
@@ -256,10 +269,22 @@ mergeFields
 mergeFields flds =
   AliasedFields <$> OMap.traverseWithKey checkFieldMergeability groups
   where
-    -- groups :: OMap.InsOrdHashMap G.Alias (NE.NESeq f)
     groups = foldr (OMap.unionWith (<>)) mempty $
              map (fmap NE.init . unAliasedFields) flds
 
+appendSelectionSets
+  :: (MonadError QErr m) => SelectionSet -> SelectionSet -> m SelectionSet
+appendSelectionSets = curry \case
+  (SelectionSetObject s1, SelectionSetObject s2) ->
+    SelectionSetObject <$> mergeObjectSelectionSets [s1, s2]
+  (SelectionSetInterface s1, SelectionSetInterface s2) ->
+    SelectionSetInterface <$> appendScopedSelectionSet s1 s2
+  (SelectionSetUnion s1, SelectionSetUnion s2) ->
+    SelectionSetUnion <$> appendScopedSelectionSet s1 s2
+  (SelectionSetNone, SelectionSetNone) -> pure SelectionSetNone
+  (_, _) -> throw500 $ "mergeSelectionSets: 'same kind' assertion failed"
+
+
 -- query q {
 --    author {
 --      id
@@ -276,29 +301,7 @@ mergeSelectionSets
   :: (MonadError QErr m) => NE.NESeq SelectionSet -> m SelectionSet
 -- mergeSelectionSets = curry $ \case
 mergeSelectionSets selectionSets =
-  case NE.head selectionSets of
-    SelectionSetObject s ->
-      SelectionSetObject <$>
-      assertingSimilar s getObjectSelectionSet mergeObjectSelectionSets
-    SelectionSetUnion s ->
-      SelectionSetUnion <$>
-      assertingSimilar s getUnionSelectionSet mergeUnionSelectionSets
-    SelectionSetInterface s ->
-      SelectionSetInterface <$>
-      assertingSimilar s getInterfaceSelectionSet mergeInterfaceSelectionSets
-    SelectionSetNone ->
-      if all (== SelectionSetNone) $ NE.tail selectionSets
-         then pure SelectionSetNone
-         else throw500 $ "mergeSelectionSets: 'same kind' assertion failed"
-  where
-    assertingSimilar
-      :: MonadError QErr m
-      => s -> (SelectionSet -> Maybe s) -> ([s] -> m s) -> m s
-    assertingSimilar s l f = do
-      let sameSelectionSets = mapMaybe l $ toList $ NE.tail selectionSets
-      if length sameSelectionSets == length (NE.tail selectionSets)
-         then f (s:sameSelectionSets)
-         else throw500 $ "mergeSelectionSets: 'same kind' assertion failed"
+  foldM appendSelectionSets (NE.head selectionSets) $ NE.tail selectionSets
 
 mergeObjectSelectionSets
   :: (MonadError QErr m) => [ObjectSelectionSet] -> m ObjectSelectionSet
@@ -337,14 +340,6 @@ mergeScopedSelectionSets
 mergeScopedSelectionSets selectionSets =
   foldM appendScopedSelectionSet emptyScopedSelectionSet selectionSets
 
-mergeInterfaceSelectionSets
-  :: (MonadError QErr m) => [InterfaceSelectionSet] -> m InterfaceSelectionSet
-mergeInterfaceSelectionSets = mergeScopedSelectionSets
-
-mergeUnionSelectionSets
-  :: (MonadError QErr m) => [UnionSelectionSet] -> m UnionSelectionSet
-mergeUnionSelectionSets = mergeScopedSelectionSets
-
 withDirectives
   :: ( MonadReader ValidationCtx m
      , MonadError QErr m
@@ -353,18 +348,19 @@ withDirectives
   => [G.Directive]
   -> m a
   -> m (Maybe a)
-withDirectives dirs act = withPathK "directives" $ do
-  dirDefs <- onLeft (mkMapWith G._dName dirs) $ \dups ->
-    throwVE $ "the following directives are used more than once: " <>
-    showNames dups
-
-  procDirs <- flip Map.traverseWithKey dirDefs $ \name dir ->
-    withPathK (G.unName name) $ do
-      dirInfo <- onNothing (Map.lookup (G._dName dir) defDirectivesMap) $
-                 throwVE $ "unexpected directive: " <> showName name
-      procArgs <- withPathK "args" $ parseArguments (_diParams dirInfo)
-                  (G._dArguments dir)
-      getIfArg procArgs
+withDirectives dirs act = do
+  procDirs <- withPathK "directives" $ do
+    dirDefs <- onLeft (mkMapWith G._dName dirs) $ \dups ->
+      throwVE $ "the following directives are used more than once: " <>
+      showNames dups
+
+    flip Map.traverseWithKey dirDefs $ \name dir ->
+      withPathK (G.unName name) $ do
+        dirInfo <- onNothing (Map.lookup (G._dName dir) defDirectivesMap) $
+                   throwVE $ "unexpected directive: " <> showName name
+        procArgs <- withPathK "args" $ parseArguments (_diParams dirInfo)
+                    (G._dArguments dir)
+        getIfArg procArgs
 
   let shouldSkip    = fromMaybe False $ Map.lookup "skip" procDirs
       shouldInclude = fromMaybe True $ Map.lookup "include" procDirs
@@ -423,21 +419,21 @@ denormalizeField fldInfo (G.Field _ name args dirs selSet) = do
       <> G.showGT fldTy <> " must have a selection of subfields"
 
     (TIObj objTyInfo, _) ->
-      SelectionSetObject <$> denormalizeSelectionSet objTyInfo selSet
+      SelectionSetObject <$> parseSelectionSet objTyInfo selSet
 
     (TIIFace _, [])  ->
       throwVE $ "field " <> showName name <> " of type "
       <> G.showGT fldTy <> " must have a selection of subfields"
 
     (TIIFace interfaceTyInfo, _) ->
-      SelectionSetInterface <$> denormalizeSelectionSet interfaceTyInfo selSet
+      SelectionSetInterface <$> parseSelectionSet interfaceTyInfo selSet
 
     (TIUnion _, [])  ->
       throwVE $ "field " <> showName name <> " of type "
       <> G.showGT fldTy <> " must have a selection of subfields"
 
     (TIUnion unionTyInfo, _) ->
-      SelectionSetUnion <$> denormalizeSelectionSet unionTyInfo selSet
+      SelectionSetUnion <$> parseSelectionSet unionTyInfo selSet
 
     (TIScalar _, []) -> return SelectionSetNone
     -- when scalar/enum and no empty set
@@ -471,29 +467,26 @@ denormalizeField fldInfo (G.Field _ name args dirs selSet) = do
 --   when (fldTy /= fragmentType) $
 --     throwVE $ "inline fragment is expected on type " <>
 --     showNamedTy fldTy <> " but found " <> showNamedTy fragmentType
---   withDirectives directives $ denormalizeObjectSelectionSet fldTyInfo selSet
+--   withDirectives directives $ parseObjectSelectionSet fldTyInfo selSet
 --   where
 --     G.InlineFragment tyM directives selSet = inlnFrag
 
-type instance DenormalizedSelectionSet ObjTyInfo = ObjectSelectionSet
-type instance DenormalizedField ObjTyInfo = Field
+type instance NormalizedSelectionSet ObjTyInfo = ObjectSelectionSet
+type instance NormalizedField ObjTyInfo = Field
+
 instance HasSelectionSet ObjTyInfo where
 
   getTypename = _otiName
   getMemberTypes = Set.singleton . _otiName
 
-  denormalizeField_ objTyInfo field = do
+  parseField_ objTyInfo field = do
     fieldInfo <- getFieldInfo (_otiName objTyInfo) (_otiFields objTyInfo) $ G._fName field
     denormalizeField fieldInfo field
 
-  mergeSelections selections =
-    mergeObjectSelectionSets $ map toObjectSelectionSet selections
-    where
-      toObjectSelectionSet = \case
-        SelectionField alias fld ->
-          ObjectSelectionSet $ AliasedFields $ OMap.singleton alias fld
-        SelectionInlineFragmentSpread selectionSet -> selectionSet
-        SelectionFragmentSpread _ selectionSet -> selectionSet
+  fieldToSelectionSet alias fld =
+    ObjectSelectionSet $ AliasedFields $ OMap.singleton alias fld
+
+  mergeNormalizedSelectionSets = mergeObjectSelectionSets
 
   fromObjectSelectionSet _ _ _ objectSelectionSet =
     objectSelectionSet
@@ -504,8 +497,8 @@ instance HasSelectionSet ObjTyInfo where
   fromUnionSelectionSet parentType _ _ unionSelectionSet =
       getMemberSelectionSet parentType unionSelectionSet
 
-type instance DenormalizedSelectionSet IFaceTyInfo = InterfaceSelectionSet
-type instance DenormalizedField IFaceTyInfo = Field
+type instance NormalizedSelectionSet IFaceTyInfo = InterfaceSelectionSet
+type instance NormalizedField IFaceTyInfo = Field
 
 instance HasSelectionSet IFaceTyInfo where
 
@@ -513,19 +506,15 @@ instance HasSelectionSet IFaceTyInfo where
   -- TODO
   getMemberTypes = _ifMemberTypes
 
-  denormalizeField_ interfaceTyInfo field = do
+  parseField_ interfaceTyInfo field = do
     fieldInfo <- getFieldInfo (_ifName interfaceTyInfo) (_ifFields interfaceTyInfo)
                  $ G._fName field
     denormalizeField fieldInfo field
 
-  mergeSelections selections =
-    mergeInterfaceSelectionSets $ map toInterfaceSelectionSet selections
-    where
-      toInterfaceSelectionSet = \case
-        SelectionField alias fld ->
-          ScopedSelectionSet (AliasedFields $ OMap.singleton alias fld) mempty
-        SelectionInlineFragmentSpread selectionSet -> selectionSet
-        SelectionFragmentSpread _ selectionSet -> selectionSet
+  fieldToSelectionSet alias field =
+    ScopedSelectionSet (AliasedFields $ OMap.singleton alias field) mempty
+
+  mergeNormalizedSelectionSets = mergeScopedSelectionSets
 
   fromObjectSelectionSet _ fragmentType _ objectSelectionSet =
     ScopedSelectionSet (AliasedFields mempty) $
@@ -541,27 +530,23 @@ instance HasSelectionSet IFaceTyInfo where
       Map.fromList $ flip map (toList commonTypes) $
       \commonType -> (commonType, getMemberSelectionSet commonType unionSelectionSet)
 
-type instance DenormalizedSelectionSet UnionTyInfo = UnionSelectionSet
-type instance DenormalizedField UnionTyInfo = Typename
+type instance NormalizedSelectionSet UnionTyInfo = UnionSelectionSet
+type instance NormalizedField UnionTyInfo = Typename
 
 instance HasSelectionSet UnionTyInfo where
 
   getTypename = _utiName
   getMemberTypes = _utiMemberTypes
 
-  denormalizeField_ unionTyInfo field = do
+  parseField_ unionTyInfo field = do
     let fieldMap = Map.singleton (_fiName typenameFld) typenameFld
     fieldInfo <- getFieldInfo (_utiName unionTyInfo) fieldMap $ G._fName field
     fmap (const Typename) <$> denormalizeField fieldInfo field
 
-  mergeSelections selections =
-    mergeUnionSelectionSets $ map toUnionSelectionSet selections
-    where
-      toUnionSelectionSet = \case
-        SelectionField alias fld ->
-          ScopedSelectionSet (AliasedFields $ OMap.singleton alias fld) mempty
-        SelectionInlineFragmentSpread selectionSet -> selectionSet
-        SelectionFragmentSpread _ selectionSet -> selectionSet
+  fieldToSelectionSet alias field =
+    ScopedSelectionSet (AliasedFields $ OMap.singleton alias field) mempty
+
+  mergeNormalizedSelectionSets = mergeScopedSelectionSets
 
   fromObjectSelectionSet _ fragmentType _ objectSelectionSet =
     ScopedSelectionSet (AliasedFields mempty) $

From fb87e2835f99409c9cb78201e0d3c2ccf99c5fa4 Mon Sep 17 00:00:00 2001
From: Vamshi Surabhi <vamshi@hasura.io>
Date: Mon, 11 May 2020 13:12:46 +0530
Subject: [PATCH 07/29] minor cleanup

---
 .../Hasura/GraphQL/Validate/SelectionSet.hs   | 23 ++-----------------
 1 file changed, 2 insertions(+), 21 deletions(-)

diff --git a/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs b/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs
index c7831b3a2411f..1a78840c26231 100644
--- a/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs
+++ b/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs
@@ -182,7 +182,8 @@ parseFragment parentTyInfo fragmentTyInfo directives fragmentSelectionSet = do
     validateSpread = do
       let commonTypes = parentTypeMembers `Set.intersection` fragmentTypeMembers
       if null commonTypes then
-          -- TODO: fragment source
+          -- TODO: better error location by capturing the fragment source -
+          -- named or otherwise
           -- throwVE $ "cannot spread fragment " <> showName name <> " defined on " <>
           throwVE $ "cannot spread fragment  defined on " <> showNamedTy fragmentType
           <> " when selecting fields of type " <> showNamedTy parentType
@@ -452,25 +453,6 @@ denormalizeField fldInfo (G.Field _ name args dirs selSet) = do
 
   withDirectives dirs $ pure $ Field  name fldBaseTy argMap fields
 
--- inlineFragmentInObjectScope
---   :: ( MonadReader ValidationCtx m
---      , MonadError QErr m
---      , MonadReusability m
---      , MonadState [G.Name] m
---      )
---   => ObjTyInfo -- type information of the field
---   -> G.InlineFragment
---   -> m (Maybe ObjectSelectionSet)
--- inlineFragmentInObjectScope fldTyInfo inlnFrag = do
---   let fldTy  = _otiName fldTyInfo
---   let fragmentType = fromMaybe fldTy tyM
---   when (fldTy /= fragmentType) $
---     throwVE $ "inline fragment is expected on type " <>
---     showNamedTy fldTy <> " but found " <> showNamedTy fragmentType
---   withDirectives directives $ parseObjectSelectionSet fldTyInfo selSet
---   where
---     G.InlineFragment tyM directives selSet = inlnFrag
-
 type instance NormalizedSelectionSet ObjTyInfo = ObjectSelectionSet
 type instance NormalizedField ObjTyInfo = Field
 
@@ -503,7 +485,6 @@ type instance NormalizedField IFaceTyInfo = Field
 instance HasSelectionSet IFaceTyInfo where
 
   getTypename = _ifName
-  -- TODO
   getMemberTypes = _ifMemberTypes
 
   parseField_ interfaceTyInfo field = do

From 8e28ed3d8d14df84480268421d6705454972dd45 Mon Sep 17 00:00:00 2001
From: rakeshkky <12475069+rakeshkky@users.noreply.github.com>
Date: Fri, 15 May 2020 17:19:32 +0530
Subject: [PATCH 08/29] generate connection SQL with complete Relay features

** ../DML/Select/* modules refactor
  -> Brand new functions and types
  -> Refactor the Annotated internal AST with better names
---
 server/src-lib/Hasura/GraphQL/Resolve.hs      |   20 +-
 .../src-lib/Hasura/GraphQL/Resolve/Action.hs  |   26 +-
 .../Hasura/GraphQL/Resolve/Mutation.hs        |    2 +-
 .../src-lib/Hasura/GraphQL/Resolve/Select.hs  |  277 ++-
 .../src-lib/Hasura/GraphQL/Resolve/Types.hs   |   12 +-
 server/src-lib/Hasura/GraphQL/Schema.hs       |   68 +-
 .../src-lib/Hasura/GraphQL/Schema/Action.hs   |    2 +-
 .../src-lib/Hasura/GraphQL/Schema/Common.hs   |   17 +-
 .../src-lib/Hasura/GraphQL/Schema/OrderBy.hs  |   36 +-
 .../src-lib/Hasura/GraphQL/Schema/Select.hs   |   51 +-
 server/src-lib/Hasura/RQL/DML/Mutation.hs     |    4 +-
 server/src-lib/Hasura/RQL/DML/Returning.hs    |   32 +-
 server/src-lib/Hasura/RQL/DML/Select.hs       |   24 +-
 .../src-lib/Hasura/RQL/DML/Select/Internal.hs | 1696 ++++++++++-------
 server/src-lib/Hasura/RQL/DML/Select/Types.hs |  512 ++---
 server/src-lib/Hasura/RQL/Types/Common.hs     |    1 +
 server/src-lib/Hasura/SQL/DML.hs              |   25 +-
 server/src-lib/Hasura/SQL/Rewrite.hs          |   20 +-
 server/src-lib/Hasura/Server/Utils.hs         |   15 +
 19 files changed, 1654 insertions(+), 1186 deletions(-)

diff --git a/server/src-lib/Hasura/GraphQL/Resolve.hs b/server/src-lib/Hasura/GraphQL/Resolve.hs
index 7f3404f63a569..235b838d29b33 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve.hs
@@ -43,8 +43,8 @@ import qualified Hasura.SQL.DML                    as S
 data QueryRootFldAST v
   = QRFPk !(DS.AnnSimpleSelG v)
   | QRFSimple !(DS.AnnSimpleSelG v)
-  | QRFAgg !(DS.AnnAggSelG v)
-  | QRFConnection !(Maybe (NonEmpty PGCol)) !(DS.ConnectionSelect v)
+  | QRFAgg !(DS.AnnAggregateSelectG v)
+  | QRFConnection !(DS.ConnectionSelect v)
   | QRFActionSelect !(DS.AnnSimpleSelG v)
   deriving (Show, Eq)
 
@@ -57,11 +57,11 @@ traverseQueryRootFldAST
   -> QueryRootFldAST a
   -> f (QueryRootFldAST b)
 traverseQueryRootFldAST f = \case
-  QRFPk s           -> QRFPk <$> DS.traverseAnnSimpleSel f s
-  QRFSimple s       -> QRFSimple <$> DS.traverseAnnSimpleSel f s
-  QRFAgg s          -> QRFAgg <$> DS.traverseAnnAggSel f s
-  QRFConnection pkey s   -> QRFConnection pkey <$> DS.traverseConnectionSelect f s
-  QRFActionSelect s -> QRFActionSelect <$> DS.traverseAnnSimpleSel f s
+  QRFPk s           -> QRFPk <$> DS.traverseAnnSimpleSelect f s
+  QRFSimple s       -> QRFSimple <$> DS.traverseAnnSimpleSelect f s
+  QRFAgg s          -> QRFAgg <$> DS.traverseAnnAggregateSelect f s
+  QRFConnection s   -> QRFConnection <$> DS.traverseConnectionSelect f s
+  QRFActionSelect s -> QRFActionSelect <$> DS.traverseAnnSimpleSelect f s
 
 toPGQuery :: QueryRootFldResolved -> Q.Query
 toPGQuery = \case
@@ -69,7 +69,7 @@ toPGQuery = \case
   QRFSimple s       -> DS.selectQuerySQL DS.JASMultipleRows s
   QRFAgg s          -> DS.selectAggQuerySQL s
   QRFActionSelect s -> DS.selectQuerySQL DS.JASSingleObject s
-  QRFConnection pkey s   -> Q.fromBuilder $ toSQL $ DS.mkConnectionSelect pkey s
+  QRFConnection s   -> Q.fromBuilder $ toSQL $ DS.mkConnectionSelect s
 
 validateHdrs
   :: (Foldable t, QErrM m) => UserInfo -> t Text -> m ()
@@ -108,9 +108,9 @@ queryFldToPGAST fld = do
     QCActionFetch ctx ->
       QRFActionSelect <$> RA.resolveAsyncActionQuery userInfo ctx fld
     QCSelectConnection pk ctx ->
-      QRFConnection pk <$> RS.convertConnectionSelect ctx fld
+      QRFConnection <$> RS.convertConnectionSelect pk ctx fld
     QCFuncConnection pk ctx ->
-      QRFConnection pk <$> RS.convertConnectionFuncQuery ctx fld
+      QRFConnection <$> RS.convertConnectionFuncQuery pk ctx fld
 
 mutFldToTx
   :: ( HasVersion
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Action.hs b/server/src-lib/Hasura/GraphQL/Resolve/Action.hs
index 6f782a179d9a0..482a810742731 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Action.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Action.hs
@@ -135,7 +135,7 @@ resolveActionMutationSync field executionContext sessionVariables = do
   selectAstUnresolved <-
     processOutputSelectionSet webhookResponseExpression outputType definitionList
     (_fType field) $ _fSelSet field
-  astResolved <- RS.traverseAnnSimpleSel resolveValTxt selectAstUnresolved
+  astResolved <- RS.traverseAnnSimpleSelect resolveValTxt selectAstUnresolved
   let jsonAggType = mkJsonAggSelect outputType
   return $ (,respHeaders) $ asSingleRowJsonResp (RS.selectQuerySQL jsonAggType astResolved) []
   where
@@ -211,35 +211,35 @@ resolveAsyncActionQuery userInfo selectOpCtx field = do
 
   annotatedFields <- fmap (map (first FieldName)) $ withSelSet (_fSelSet field) $ \fld ->
     case _fName fld of
-      "__typename" -> return $ RS.FExp $ G.unName $ G.unNamedType $ _fType field
+      "__typename" -> return $ RS.AFExpression $ G.unName $ G.unNamedType $ _fType field
       "output"     -> do
         -- See Note [Resolving async action query/subscription]
         let inputTableArgument = RS.AETableRow $ Just $ Iden "response_payload"
             ActionSelectOpContext outputType definitionList = selectOpCtx
             jsonAggSelect = mkJsonAggSelect outputType
-        (RS.FComputedField . RS.CFSTable jsonAggSelect)
+        (RS.AFComputedField . RS.CFSTable jsonAggSelect)
           <$> processOutputSelectionSet inputTableArgument outputType
               definitionList (_fType fld) (_fSelSet fld)
 
       -- The metadata columns
-      "id"         -> return $ mkAnnFldFromPGCol "id" PGUUID
-      "created_at" -> return $ mkAnnFldFromPGCol "created_at" PGTimeStampTZ
-      "errors"     -> return $ mkAnnFldFromPGCol "errors" PGJSONB
+      "id"         -> return $ mkAnnFieldFromPGCol "id" PGUUID
+      "created_at" -> return $ mkAnnFieldFromPGCol "created_at" PGTimeStampTZ
+      "errors"     -> return $ mkAnnFieldFromPGCol "errors" PGJSONB
       G.Name t     -> throw500 $ "unexpected field in actions' httpResponse : " <> t
 
   let tableFromExp = RS.FromTable actionLogTable
-      tableArguments = RS.noTableArgs
-                       { RS._taWhere = Just $ mkTableBoolExpression actionId}
+      tableArguments = RS.noSelectArgs
+                       { RS._saWhere = Just $ mkTableBoolExpression actionId}
       tablePermissions = RS.TablePerm annBoolExpTrue Nothing
-      selectAstUnresolved = RS.AnnSelG annotatedFields tableFromExp tablePermissions
+      selectAstUnresolved = RS.AnnSelectG annotatedFields tableFromExp tablePermissions
                             tableArguments stringifyNumerics
   return selectAstUnresolved
   where
     actionLogTable = QualifiedObject (SchemaName "hdb_catalog") (TableName "hdb_action_log")
 
     -- TODO:- Avoid using PGColumnInfo
-    mkAnnFldFromPGCol column columnType =
-      flip RS.mkAnnColField Nothing $
+    mkAnnFieldFromPGCol column columnType =
+      flip RS.mkAnnColumnField Nothing $
       PGColumnInfo (unsafePGCol column) (G.Name column) 0 (PGColumnScalar columnType) True Nothing
 
     parseActionId annInpValue = mkParameterizablePGValue <$> asPGColumnValue annInpValue
@@ -469,8 +469,8 @@ processOutputSelectionSet
 processOutputSelectionSet tableRowInput actionOutputType definitionList fldTy flds = do
   stringifyNumerics <- stringifyNum <$> asks getter
   annotatedFields <- processTableSelectionSet fldTy flds
-  let annSel = RS.AnnSelG annotatedFields selectFrom
-                  RS.noTablePermissions RS.noTableArgs stringifyNumerics
+  let annSel = RS.AnnSelectG annotatedFields selectFrom
+                  RS.noTablePermissions RS.noSelectArgs stringifyNumerics
   pure annSel
   where
     jsonbToPostgresRecordFunction =
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Mutation.hs b/server/src-lib/Hasura/GraphQL/Resolve/Mutation.hs
index bfcb9d992eb85..d3ccbff7e9b8d 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Mutation.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Mutation.hs
@@ -50,7 +50,7 @@ resolveMutationFields ty selSet = fmap (map (first FieldName)) $
     "returning"     -> do
       annFlds <- processTableSelectionSet (_fType fld) $ _fSelSet fld
       annFldsResolved <- traverse
-        (traverse (RS.traverseAnnFld convertPGValueToTextValue)) annFlds
+        (traverse (RS.traverseAnnField convertPGValueToTextValue)) annFlds
       return $ RR.MRet annFldsResolved
     G.Name t        -> throw500 $ "unexpected field in mutation resp : " <> t
   where
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Select.hs b/server/src-lib/Hasura/GraphQL/Resolve/Select.hs
index c31072f9e3d9c..d47c48543e059 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Select.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Select.hs
@@ -16,11 +16,15 @@ import           Data.Has
 import           Data.Parser.JSONPath
 import           Hasura.Prelude
 
+import qualified Data.Aeson                        as J
+import qualified Data.Aeson.Internal               as J
+import qualified Data.ByteString.Lazy              as BL
 import qualified Data.HashMap.Strict               as Map
 import qualified Data.HashMap.Strict.InsOrd        as OMap
 import qualified Data.List.NonEmpty                as NE
 import qualified Data.Sequence                     as Seq
 import qualified Data.Text                         as T
+import qualified Data.Text.Conversions             as TC
 import qualified Language.GraphQL.Draft.Syntax     as G
 
 import qualified Hasura.RQL.DML.Select             as RS
@@ -29,11 +33,12 @@ import qualified Hasura.SQL.DML                    as S
 import           Hasura.GraphQL.Resolve.BoolExp
 import           Hasura.GraphQL.Resolve.Context
 import           Hasura.GraphQL.Resolve.InputValue
-import           Hasura.GraphQL.Schema             (isAggFld)
+import           Hasura.GraphQL.Schema             (isAggregateField)
 import           Hasura.GraphQL.Validate.Field
 import           Hasura.GraphQL.Validate.Types
 import           Hasura.RQL.DML.Internal           (onlyPositiveInt)
 import           Hasura.RQL.Types
+import           Hasura.Server.Utils
 import           Hasura.SQL.Types
 import           Hasura.SQL.Value
 
@@ -46,27 +51,27 @@ jsonPathToColExp t = case parseJSONPath t of
     elToColExp (Index i) = S.SELit $ T.pack (show i)
 
 
-argsToColOp :: (MonadReusability m, MonadError QErr m) => ArgsMap -> m (Maybe RS.ColOp)
-argsToColOp args = maybe (return Nothing) toOp $ Map.lookup "path" args
+argsToColumnOp :: (MonadReusability m, MonadError QErr m) => ArgsMap -> m (Maybe RS.ColumnOp)
+argsToColumnOp args = maybe (return Nothing) toOp $ Map.lookup "path" args
   where
-    toJsonPathExp = fmap (RS.ColOp S.jsonbPathOp) . jsonPathToColExp
+    toJsonPathExp = fmap (RS.ColumnOp S.jsonbPathOp) . jsonPathToColExp
     toOp v = asPGColTextM v >>= traverse toJsonPathExp
 
-type AnnFlds = RS.AnnFldsG UnresolvedVal
+type AnnFields = RS.AnnFieldsG UnresolvedVal
 
 resolveComputedField
   :: ( MonadReusability m, MonadReader r m, Has FieldMap r
      , Has OrdByCtx r, Has SQLGenCtx r, MonadError QErr m
      )
-  => ComputedField -> Field -> m (RS.ComputedFieldSel UnresolvedVal)
+  => ComputedField -> Field -> m (RS.ComputedFieldSelect UnresolvedVal)
 resolveComputedField computedField fld = fieldAsPath fld $ do
   funcArgs <- parseFunctionArgs argSeq argFn $ Map.lookup "args" $ _fArguments fld
   let argsWithTableArgument = withTableArgument funcArgs
   case fieldType of
     CFTScalar scalarTy -> do
-      colOpM <- argsToColOp $ _fArguments fld
+      colOpM <- argsToColumnOp $ _fArguments fld
       pure $ RS.CFSScalar $
-        RS.ComputedFieldScalarSel qf argsWithTableArgument scalarTy colOpM
+        RS.ComputedFieldScalarSelect qf argsWithTableArgument scalarTy colOpM
     CFTTable (ComputedFieldTable _ cols permFilter permLimit) -> do
       let functionFrom = RS.FromFunction qf argsWithTableArgument Nothing
       RS.CFSTable RS.JASMultipleRows <$> fromField functionFrom cols permFilter permLimit fld
@@ -87,48 +92,52 @@ processTableSelectionSet
   :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
      , Has OrdByCtx r, Has SQLGenCtx r
      )
-  => G.NamedType -> SelSet -> m AnnFlds
+  => G.NamedType -> SelSet -> m AnnFields
 processTableSelectionSet fldTy flds =
   forM (toList flds) $ \fld -> do
     let fldName = _fName fld
     let rqlFldName = FieldName $ G.unName $ G.unAlias $ _fAlias fld
     (rqlFldName,) <$> case fldName of
-      "__typename" -> return $ RS.FExp $ G.unName $ G.unNamedType fldTy
+      "__typename" -> return $ RS.AFExpression $ G.unName $ G.unNamedType fldTy
       _ -> do
         fldInfo <- getFldInfo fldTy fldName
         case fldInfo of
           RFPGColumn colInfo ->
-            RS.mkAnnColField colInfo <$> argsToColOp (_fArguments fld)
+            RS.mkAnnColumnField colInfo <$> argsToColumnOp (_fArguments fld)
           RFComputedField computedField ->
-            RS.FComputedField <$> resolveComputedField computedField fld
-          RFRelationship (RelationshipField relInfo isAgg colGNameMap tableFilter tableLimit) -> do
+            RS.AFComputedField <$> resolveComputedField computedField fld
+          RFRelationship (RelationshipField relInfo fieldKind colGNameMap tableFilter tableLimit) -> do
             let relTN = riRTable relInfo
                 colMapping = riMapping relInfo
                 rn = riName relInfo
-            if isAgg then do
-              aggSel <- fromAggField (RS.FromTable relTN) colGNameMap tableFilter tableLimit fld
-              return $ RS.FArr $ RS.ASAgg $ RS.AnnRelG rn colMapping aggSel
-            else do
-              annSel <- fromField (RS.FromTable relTN) colGNameMap tableFilter tableLimit fld
-              let annRel = RS.AnnRelG rn colMapping annSel
-              return $ case riType relInfo of
-                ObjRel -> RS.FObj annRel
-                ArrRel -> RS.FArr $ RS.ASSimple annRel
-
-type TableAggFlds = RS.TableAggFldsG UnresolvedVal
+            case fieldKind of
+              RFKSimple -> do
+                annSel <- fromField (RS.FromTable relTN) colGNameMap tableFilter tableLimit fld
+                let annRel = RS.AnnRelationSelectG rn colMapping annSel
+                pure $ case riType relInfo of
+                  ObjRel -> RS.AFObjectRelation annRel
+                  ArrRel -> RS.AFArrayRelation $ RS.ASSimple annRel
+              RFKAggregate -> do
+                aggSel <- fromAggField (RS.FromTable relTN) colGNameMap tableFilter tableLimit fld
+                pure $ RS.AFArrayRelation $ RS.ASAggregate $ RS.AnnRelationSelectG rn colMapping aggSel
+              RFKConnection pkCols -> do
+                connSel <- fromConnectionField (RS.FromTable relTN) pkCols tableFilter tableLimit fld
+                pure $ RS.AFArrayRelation $ RS.ASConnection $ RS.AnnRelationSelectG rn colMapping connSel
+
+type TableAggregateFields = RS.TableAggregateFieldsG UnresolvedVal
 
 fromAggSelSet
   :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
      , Has OrdByCtx r, Has SQLGenCtx r
      )
-  => PGColGNameMap -> G.NamedType -> SelSet -> m TableAggFlds
+  => PGColGNameMap -> G.NamedType -> SelSet -> m TableAggregateFields
 fromAggSelSet colGNameMap fldTy selSet = fmap toFields $
   withSelSet selSet $ \f -> do
     let fTy = _fType f
         fSelSet = _fSelSet f
     case _fName f of
       "__typename" -> return $ RS.TAFExp $ G.unName $ G.unNamedType fldTy
-      "aggregate"  -> RS.TAFAgg <$> convertAggFld colGNameMap fTy fSelSet
+      "aggregate"  -> RS.TAFAgg <$> convertAggregateField colGNameMap fTy fSelSet
       "nodes"      -> RS.TAFNodes <$> processTableSelectionSet fTy fSelSet
       G.Name t     -> throw500 $ "unexpected field in _agg node: " <> t
 
@@ -145,7 +154,7 @@ fromConnectionSelSet fldTy selSet = fmap toFields $
       "__typename" -> return $ RS.ConnectionTypename $ G.unName $ G.unNamedType fldTy
       "pageInfo"   -> RS.ConnectionPageInfo <$> parsePageInfoSelectionSet fTy fSelSet
       "edges"      -> RS.ConnectionEdges <$> parseEdgeSelectionSet fTy fSelSet
-      -- "aggregate"  -> RS.TAFAgg <$> convertAggFld colGNameMap fTy fSelSet
+      -- "aggregate"  -> RS.TAFAgg <$> convertAggregateField colGNameMap fTy fSelSet
       -- "nodes"      -> RS.TAFNodes <$> processTableSelectionSet fTy fSelSet
       G.Name t     -> throw500 $ "unexpected field in _connection node: " <> t
 
@@ -160,7 +169,7 @@ parseEdgeSelectionSet fldTy selSet = fmap toFields $
         fSelSet = _fSelSet f
     case _fName f of
       "__typename" -> pure $ RS.EdgeTypename $ G.unName $ G.unNamedType fldTy
-      "cursor"     -> pure $ RS.EdgeCursor
+      "cursor"     -> pure RS.EdgeCursor
       "node"       -> RS.EdgeNode <$> processTableSelectionSet fTy fSelSet
       G.Name t     -> throw500 $ "unexpected field in Edge node: " <> t
 
@@ -171,40 +180,41 @@ parsePageInfoSelectionSet fldTy selSet =
   fmap toFields $ withSelSet selSet $ \f ->
     case _fName f of
       "__typename"      -> pure $ RS.PageInfoTypename $ G.unName $ G.unNamedType fldTy
-      "hasNextPage"     -> pure $ RS.PageInfoHasNextPage
-      "hasPreviousPage" -> pure $ RS.PageInfoHasPreviousPage
-      "startCursor"     -> pure $ RS.PageInfoStartCursor
-      "endCursor"       -> pure $ RS.PageInfoEndCursor
-      -- "aggregate"  -> RS.TAFAgg <$> convertAggFld colGNameMap fTy fSelSet
+      "hasNextPage"     -> pure RS.PageInfoHasNextPage
+      "hasPreviousPage" -> pure RS.PageInfoHasPreviousPage
+      "startCursor"     -> pure RS.PageInfoStartCursor
+      "endCursor"       -> pure RS.PageInfoEndCursor
+      -- "aggregate"  -> RS.TAFAgg <$> convertAggregateField colGNameMap fTy fSelSet
       -- "nodes"      -> RS.TAFNodes <$> processTableSelectionSet fTy fSelSet
       G.Name t          -> throw500 $ "unexpected field in PageInfo node: " <> t
 
-type TableArgs = RS.TableArgsG UnresolvedVal
+type SelectArgs = RS.SelectArgsG UnresolvedVal
 
-parseTableArgs
+parseSelectArgs
   :: ( MonadReusability m, MonadError QErr m, MonadReader r m
      , Has FieldMap r, Has OrdByCtx r
      )
-  => PGColGNameMap -> ArgsMap -> m TableArgs
-parseTableArgs colGNameMap args = do
+  => PGColGNameMap -> ArgsMap -> m SelectArgs
+parseSelectArgs colGNameMap args = do
   whereExpM  <- withArgM args "where" parseBoolExp
   ordByExpML <- withArgM args "order_by" parseOrderBy
   let ordByExpM = NE.nonEmpty =<< ordByExpML
-  limitExpM  <- withArgM args "limit" parseLimit
+  limitExpM  <- withArgM args "limit" $
+                parseNonNegativeInt "expecting Integer value for \"limit\""
   offsetExpM <- withArgM args "offset" $ asPGColumnValue >=> openOpaqueValue >=> txtConverter
   distOnColsML <- withArgM args "distinct_on" $ parseColumns colGNameMap
   let distOnColsM = NE.nonEmpty =<< distOnColsML
   mapM_ (validateDistOn ordByExpM) distOnColsM
-  return $ RS.TableArgs whereExpM ordByExpM limitExpM offsetExpM distOnColsM
+  return $ RS.SelectArgs whereExpM ordByExpM limitExpM offsetExpM distOnColsM
   where
     validateDistOn Nothing _ = return ()
     validateDistOn (Just ordBys) cols = withPathK "args" $ do
       let colsLen = length cols
           initOrdBys = take colsLen $ toList ordBys
           initOrdByCols = flip mapMaybe initOrdBys $ \ob ->
-            case obiColumn ob of
-              RS.AOCPG pgCol -> Just pgCol
-              _              -> Nothing
+            case obiColumn  ob of
+              RS.AOCColumn pgCol -> Just $ pgiColumn pgCol
+              _                  -> Nothing
           isValid = (colsLen == length initOrdByCols)
                     && all (`elem` initOrdByCols) (toList cols)
 
@@ -223,12 +233,12 @@ fromField
   -> Maybe Int
   -> Field -> m AnnSimpleSelect
 fromField selFrom colGNameMap permFilter permLimitM fld = fieldAsPath fld $ do
-  tableArgs <- parseTableArgs colGNameMap args
+  tableArgs <- parseSelectArgs colGNameMap args
   annFlds   <- processTableSelectionSet (_fType fld) $ _fSelSet fld
   let unresolvedPermFltr = fmapAnnBoolExp partialSQLExpToUnresolvedVal permFilter
   let tabPerm = RS.TablePerm unresolvedPermFltr permLimitM
   strfyNum <- stringifyNum <$> asks getter
-  return $ RS.AnnSelG annFlds selFrom tabPerm tableArgs strfyNum
+  return $ RS.AnnSelectG annFlds selFrom tabPerm tableArgs strfyNum
   where
     args = _fArguments fld
 
@@ -249,7 +259,8 @@ parseOrderBy
      , MonadReader r m
      , Has OrdByCtx r
      )
-  => AnnInpVal -> m [RS.AnnOrderByItemG UnresolvedVal]
+  => AnnInpVal
+  -> m [RS.AnnOrderByItemG UnresolvedVal]
 parseOrderBy = fmap concat . withArray f
   where
     f _ = mapM (withObject (getAnnObItems id))
@@ -260,7 +271,7 @@ getAnnObItems
      , MonadReader r m
      , Has OrdByCtx r
      )
-  => (RS.AnnObColG UnresolvedVal -> RS.AnnObColG UnresolvedVal)
+  => (RS.AnnOrderByElement UnresolvedVal -> RS.AnnOrderByElement UnresolvedVal)
   -> G.NamedType
   -> AnnGObject
   -> m [RS.AnnOrderByItemG UnresolvedVal]
@@ -272,7 +283,7 @@ getAnnObItems f nt obj = do
       <> showNamedTy nt <> " map"
     case ordByItem of
       OBIPGCol ci -> do
-        let aobCol = f $ RS.AOCPG $ pgiColumn ci
+        let aobCol = f $ RS.AOCColumn ci
         (_, enumValM) <- asEnumValM v
         ordByItemM <- forM enumValM $ \enumVal -> do
           (ordTy, nullsOrd) <- parseOrderByEnum enumVal
@@ -281,13 +292,13 @@ getAnnObItems f nt obj = do
 
       OBIRel ri fltr -> do
         let unresolvedFltr = fmapAnnBoolExp partialSQLExpToUnresolvedVal fltr
-        let annObColFn = f . RS.AOCObj ri unresolvedFltr
+        let annObColFn = f . RS.AOCObjectRelation ri unresolvedFltr
         flip withObjectM v $ \nameTy objM ->
           maybe (pure []) (getAnnObItems annObColFn nameTy) objM
 
       OBIAgg ri relColGNameMap fltr -> do
         let unresolvedFltr = fmapAnnBoolExp partialSQLExpToUnresolvedVal fltr
-        let aobColFn = f . RS.AOCAgg ri unresolvedFltr
+        let aobColFn = f . RS.AOCArrayAggregation ri unresolvedFltr
         flip withObjectM v $ \_ objM ->
           maybe (pure []) (parseAggOrdBy relColGNameMap aobColFn) objM
 
@@ -298,7 +309,7 @@ mkOrdByItemG ordTy aobCol nullsOrd =
 parseAggOrdBy
   :: (MonadReusability m, MonadError QErr m)
   => PGColGNameMap
-  -> (RS.AnnAggOrdBy -> RS.AnnObColG UnresolvedVal)
+  -> (RS.AnnAggregateOrderBy -> RS.AnnOrderByElement UnresolvedVal)
   -> AnnGObject
   -> m [RS.AnnOrderByItemG UnresolvedVal]
 parseAggOrdBy colGNameMap f annObj =
@@ -311,14 +322,14 @@ parseAggOrdBy colGNameMap f annObj =
           return $ mkOrdByItemG ordTy (f RS.AAOCount) nullsOrd
         return $ maybe [] pure ordByItemM
 
-      G.Name opT ->
+      G.Name opText ->
         flip withObject obVal $ \_ opObObj -> fmap catMaybes $
           forM (OMap.toList opObObj) $ \(colName, eVal) -> do
             (_, enumValM) <- asEnumValM eVal
             forM enumValM $ \enumVal -> do
               (ordTy, nullsOrd) <- parseOrderByEnum enumVal
-              col <- pgiColumn <$> resolvePGCol colGNameMap colName
-              let aobCol = f $ RS.AAOOp opT col
+              col <- resolvePGCol colGNameMap colName
+              let aobCol = f $ RS.AAOOp opText col
               return $ mkOrdByItemG ordTy aobCol nullsOrd
 
 parseOrderByEnum
@@ -335,15 +346,14 @@ parseOrderByEnum = \case
   G.EnumValue v                   -> throw500 $
     "enum value " <> showName v <> " not found in type order_by"
 
-parseLimit :: (MonadReusability m, MonadError QErr m) => AnnInpVal -> m Int
-parseLimit v = do
+parseNonNegativeInt
+  :: (MonadReusability m, MonadError QErr m) => Text -> AnnInpVal -> m Int
+parseNonNegativeInt errMsg v = do
   pgColVal <- openOpaqueValue =<< asPGColumnValue v
-  limit <- maybe noIntErr return . pgColValueToInt . pstValue $ _apvValue pgColVal
+  limit <- maybe (throwVE errMsg) return . pgColValueToInt . pstValue $ _apvValue pgColVal
   -- validate int value
   onlyPositiveInt limit
   return limit
-  where
-    noIntErr = throwVE "expecting Integer value for \"limit\""
 
 type AnnSimpleSel = RS.AnnSimpleSelG UnresolvedVal
 
@@ -364,9 +374,9 @@ fromFieldByPKey tn colArgMap permFilter fld = fieldAsPath fld $ do
       unresolvedPermFltr = fmapAnnBoolExp partialSQLExpToUnresolvedVal
                            permFilter
       tabPerm = RS.TablePerm unresolvedPermFltr Nothing
-      tabArgs = RS.noTableArgs { RS._taWhere = Just boolExp}
+      tabArgs = RS.noSelectArgs { RS._saWhere = Just boolExp}
   strfyNum <- stringifyNum <$> asks getter
-  return $ RS.AnnSelG annFlds tabFrom tabPerm tabArgs strfyNum
+  return $ RS.AnnSelectG annFlds tabFrom tabPerm tabArgs strfyNum
   where
     fldTy = _fType fld
 
@@ -423,19 +433,19 @@ convertCount colGNameMap args = do
 toFields :: [(T.Text, a)] -> RS.Fields a
 toFields = map (first FieldName)
 
-convertColFlds
+convertColumnFields
   :: (MonadError QErr m)
-  => PGColGNameMap -> G.NamedType -> SelSet -> m RS.ColFlds
-convertColFlds colGNameMap ty selSet = fmap toFields $
+  => PGColGNameMap -> G.NamedType -> SelSet -> m RS.ColumnFields
+convertColumnFields colGNameMap ty selSet = fmap toFields $
   withSelSet selSet $ \fld ->
     case _fName fld of
       "__typename" -> return $ RS.PCFExp $ G.unName $ G.unNamedType ty
-      n            -> (RS.PCFCol . pgiColumn) <$> resolvePGCol colGNameMap n
+      n            -> RS.PCFCol . pgiColumn <$> resolvePGCol colGNameMap n
 
-convertAggFld
+convertAggregateField
   :: (MonadReusability m, MonadError QErr m)
-  => PGColGNameMap -> G.NamedType -> SelSet -> m RS.AggFlds
-convertAggFld colGNameMap ty selSet = fmap toFields $
+  => PGColGNameMap -> G.NamedType -> SelSet -> m RS.AggregateFields
+convertAggregateField colGNameMap ty selSet = fmap toFields $
   withSelSet selSet $ \fld -> do
     let fType = _fType fld
         fSelSet = _fSelSet fld
@@ -443,14 +453,14 @@ convertAggFld colGNameMap ty selSet = fmap toFields $
       "__typename" -> return $ RS.AFExp $ G.unName $ G.unNamedType ty
       "count"      -> RS.AFCount <$> convertCount colGNameMap (_fArguments fld)
       n            -> do
-        colFlds <- convertColFlds colGNameMap fType fSelSet
-        unless (isAggFld n) $ throwInvalidFld n
-        return $ RS.AFOp $ RS.AggOp (G.unName n) colFlds
+        colFlds <- convertColumnFields colGNameMap fType fSelSet
+        unless (isAggregateField n) $ throwInvalidFld n
+        return $ RS.AFOp $ RS.AggregateOp (G.unName n) colFlds
   where
       throwInvalidFld (G.Name t) =
         throw500 $ "unexpected field in _aggregate node: " <> t
 
-type AnnAggSel = RS.AnnAggSelG UnresolvedVal
+type AnnAggregateSelect = RS.AnnAggregateSelectG UnresolvedVal
 
 fromAggField
   :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
@@ -460,15 +470,15 @@ fromAggField
   -> PGColGNameMap
   -> AnnBoolExpPartialSQL
   -> Maybe Int
-  -> Field -> m AnnAggSel
+  -> Field -> m AnnAggregateSelect
 fromAggField selectFrom colGNameMap permFilter permLimit fld = fieldAsPath fld $ do
-  tableArgs   <- parseTableArgs colGNameMap args
+  tableArgs   <- parseSelectArgs colGNameMap args
   aggSelFlds  <- fromAggSelSet colGNameMap (_fType fld) (_fSelSet fld)
   let unresolvedPermFltr =
         fmapAnnBoolExp partialSQLExpToUnresolvedVal permFilter
   let tabPerm = RS.TablePerm unresolvedPermFltr permLimit
   strfyNum <- stringifyNum <$> asks getter
-  return $ RS.AnnSelG aggSelFlds selectFrom tabPerm tableArgs strfyNum
+  return $ RS.AnnSelectG aggSelFlds selectFrom tabPerm tableArgs strfyNum
   where
     args = _fArguments fld
 
@@ -477,37 +487,118 @@ fromConnectionField
      , Has OrdByCtx r, Has SQLGenCtx r
      )
   => RS.SelectFromG UnresolvedVal
+  -> NonEmpty PGColumnInfo
   -> AnnBoolExpPartialSQL
   -> Maybe Int
   -> Field -> m (RS.ConnectionSelect UnresolvedVal)
-fromConnectionField selectFrom permFilter permLimit fld = fieldAsPath fld $ do
-  tableArgs   <- parseConnectionArgs args
-  aggSelFlds  <- fromConnectionSelSet (_fType fld) (_fSelSet fld)
+fromConnectionField selectFrom pkCols permFilter permLimit fld = fieldAsPath fld $ do
+  (tableArgs, slice, split)   <- parseConnectionArgs pkCols args
+  connSelFlds  <- fromConnectionSelSet (_fType fld) (_fSelSet fld)
+  strfyNum <- stringifyNum <$> asks getter
   let unresolvedPermFltr =
         fmapAnnBoolExp partialSQLExpToUnresolvedVal permFilter
-  let tabPerm = RS.TablePerm unresolvedPermFltr permLimit
-  strfyNum <- stringifyNum <$> asks getter
-  return $ RS.AnnSelG aggSelFlds selectFrom tabPerm tableArgs strfyNum
+      tabPerm = RS.TablePerm unresolvedPermFltr permLimit
+      annSel = RS.AnnSelectG connSelFlds selectFrom tabPerm tableArgs strfyNum
+  pure $ RS.ConnectionSelect pkCols split slice annSel
   where
     args = _fArguments fld
 
 parseConnectionArgs
-  :: ( MonadReusability m, MonadError QErr m, MonadReader r m
+  :: forall r m.
+     ( MonadReusability m, MonadError QErr m, MonadReader r m
      , Has FieldMap r, Has OrdByCtx r
      )
-  => ArgsMap -> m TableArgs
-parseConnectionArgs args = do
+  => NonEmpty PGColumnInfo
+  -> ArgsMap
+  -> m ( SelectArgs
+       , Maybe RS.ConnectionSlice
+       , Maybe (NE.NonEmpty (RS.ConnectionSplit UnresolvedVal))
+       )
+parseConnectionArgs pKeyColumns args = do
   whereExpM  <- withArgM args "where" parseBoolExp
   ordByExpML <- withArgM args "order_by" parseOrderBy
+
+  slice <- case (Map.lookup "first" args, Map.lookup "last" args) of
+    (Nothing, Nothing) -> pure Nothing
+    (Just _, Just _)   -> throwVE "\"first\" and \"last\" are not allowed at once"
+    (Just v, Nothing)  -> Just . RS.SliceFirst <$> parseNonNegativeInt
+      "expecting Integer value for \"first\"" v
+    (Nothing, Just v)  -> Just . RS.SliceLast <$> parseNonNegativeInt
+      "expecting Integer value for \"last\"" v
+
+  maybeSplit <- case (Map.lookup "after" args, Map.lookup "before" args) of
+    (Nothing, Nothing) -> pure Nothing
+    (Just _, Just _)   -> throwVE "\"after\" and \"before\" are not allowed at once"
+    (Just v, Nothing)  -> fmap ((RS.CSKAfter,) . TC.convertText) <$> asPGColTextM v
+    (Nothing, Just v)  -> fmap ((RS.CSKBefore,) . TC.convertText) <$> asPGColTextM v
+
   let ordByExpM = NE.nonEmpty =<< ordByExpML
-  -- limitExpM  <- withArgM args "limit" parseLimit
-  return $ RS.TableArgs whereExpM ordByExpM Nothing Nothing Nothing
+      tableArgs = RS.SelectArgs whereExpM ordByExpM Nothing Nothing Nothing
+
+  split <- mapM (uncurry (validateConnectionSplit ordByExpM)) maybeSplit
+  pure (tableArgs, slice, split)
+  where
+    validateConnectionSplit
+      :: Maybe (NonEmpty (RS.AnnOrderByItemG UnresolvedVal))
+      -> RS.ConnectionSplitKind
+      -> Maybe (TC.Base64 BL.ByteString)
+      -> m (NonEmpty (RS.ConnectionSplit UnresolvedVal))
+    validateConnectionSplit maybeOrderBys splitKind maybeCursorSplit = do
+      cursorSplit <- maybe throwInvalidCursor pure maybeCursorSplit
+      cursorValue <- either (const throwInvalidCursor) pure $
+                      J.eitherDecode $ TC.unBase64 cursorSplit
+      case maybeOrderBys of
+        Nothing -> forM pKeyColumns $
+          \pgColumnInfo -> do
+            let columnJsonPath = [J.Key $ getPGColTxt $ pgiColumn pgColumnInfo]
+            pgColumnValue <- maybe throwInvalidCursor pure $ iResultToMaybe $
+                             executeJSONPath columnJsonPath cursorValue
+            pgValue <- parsePGScalarValue (pgiType pgColumnInfo) pgColumnValue
+            let unresolvedValue = UVPG $ AnnPGVal Nothing False pgValue
+            pure $ RS.ConnectionSplit splitKind unresolvedValue $
+                   OrderByItemG Nothing (RS.AOCColumn pgColumnInfo) Nothing
+        Just orderBys ->
+          forM orderBys $ \orderBy -> do
+            let OrderByItemG orderType annObCol nullsOrder = orderBy
+            orderByItemValue <- maybe throwInvalidCursor pure $ iResultToMaybe $
+                                executeJSONPath (getPathFromOrderBy annObCol) cursorValue
+            pgValue <- parsePGScalarValue (getOrderByColumnType annObCol) orderByItemValue
+            let unresolvedValue = UVPG $ AnnPGVal Nothing False pgValue
+            pure $ RS.ConnectionSplit splitKind unresolvedValue $
+                   OrderByItemG orderType (() <$ annObCol) nullsOrder
+      where
+        throwInvalidCursor = throwVE "the \"after\" or \"before\" cursor is invalid"
+
+        iResultToMaybe = \case
+          J.ISuccess v -> Just v
+          J.IError{}   -> Nothing
+
+        getPathFromOrderBy = \case
+          RS.AOCColumn pgColInfo ->
+            let pathElement = J.Key $ getPGColTxt $ pgiColumn pgColInfo
+            in [pathElement]
+          RS.AOCObjectRelation relInfo _ obCol ->
+            let pathElement = J.Key $ relNameToTxt $ riName relInfo
+            in pathElement : getPathFromOrderBy obCol
+          RS.AOCArrayAggregation relInfo _ aggOb ->
+            let fieldName = J.Key $ relNameToTxt (riName relInfo) <> "_aggregate"
+            in fieldName : case aggOb of
+                 RS.AAOCount    -> [J.Key "count"]
+                 RS.AAOOp t col -> [J.Key t, J.Key $ getPGColTxt $ pgiColumn col]
+
+        getOrderByColumnType = \case
+          RS.AOCColumn pgColInfo -> pgiType pgColInfo
+          RS.AOCObjectRelation _ _ obCol -> getOrderByColumnType obCol
+          RS.AOCArrayAggregation _ _ aggOb ->
+            case aggOb of
+              RS.AAOCount        -> PGColumnScalar PGInteger
+              RS.AAOOp _ colInfo -> pgiType colInfo
 
 convertAggSelect
   :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
      , Has OrdByCtx r, Has SQLGenCtx r
      )
-  => SelOpCtx -> Field -> m (RS.AnnAggSelG UnresolvedVal)
+  => SelOpCtx -> Field -> m (RS.AnnAggregateSelectG UnresolvedVal)
 convertAggSelect opCtx fld =
   withPathK "selectionSet" $
   fromAggField (RS.FromTable qt) colGNameMap permFilter permLimit fld
@@ -518,10 +609,10 @@ convertConnectionSelect
   :: ( MonadReusability m, MonadError QErr m, MonadReader r m, Has FieldMap r
      , Has OrdByCtx r, Has SQLGenCtx r
      )
-  => SelOpCtx -> Field -> m (RS.ConnectionSelect UnresolvedVal)
-convertConnectionSelect opCtx fld =
+  => NonEmpty PGColumnInfo -> SelOpCtx -> Field -> m (RS.ConnectionSelect UnresolvedVal)
+convertConnectionSelect pkCols opCtx fld =
   withPathK "selectionSet" $
-  fromConnectionField (RS.FromTable qt) permFilter permLimit fld
+  fromConnectionField (RS.FromTable qt) pkCols permFilter permLimit fld
   where
     SelOpCtx qt _ _ permFilter permLimit = opCtx
 
@@ -600,7 +691,7 @@ convertFuncQueryAgg
      , Has OrdByCtx r
      , Has SQLGenCtx r
      )
-  => FuncQOpCtx -> Field -> m AnnAggSel
+  => FuncQOpCtx -> Field -> m AnnAggregateSelect
 convertFuncQueryAgg funcOpCtx fld =
   withPathK "selectionSet" $ fieldAsPath fld $ do
     selectFrom <- makeFunctionSelectFrom qf argSeq fld
@@ -616,10 +707,10 @@ convertConnectionFuncQuery
      , Has OrdByCtx r
      , Has SQLGenCtx r
      )
-  => FuncQOpCtx -> Field -> m (RS.ConnectionSelect UnresolvedVal)
-convertConnectionFuncQuery funcOpCtx fld =
+  => NonEmpty PGColumnInfo -> FuncQOpCtx -> Field -> m (RS.ConnectionSelect UnresolvedVal)
+convertConnectionFuncQuery pkCols funcOpCtx fld =
   withPathK "selectionSet" $ fieldAsPath fld $ do
     selectFrom <- makeFunctionSelectFrom qf argSeq fld
-    fromConnectionField selectFrom permFilter permLimit fld
+    fromConnectionField selectFrom pkCols permFilter permLimit fld
   where
     FuncQOpCtx qf argSeq _ _ permFilter permLimit = funcOpCtx
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Types.hs b/server/src-lib/Hasura/GraphQL/Resolve/Types.hs
index 297778a9a0e62..79461ea059589 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Types.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Types.hs
@@ -29,12 +29,12 @@ import qualified Hasura.SQL.DML                 as S
 
 data QueryCtx
   = QCSelect !SelOpCtx
-  | QCSelectConnection !(Maybe (NonEmpty PGCol)) !SelOpCtx
+  | QCSelectConnection !(NonEmpty PGColumnInfo) !SelOpCtx
   | QCSelectPkey !SelPkOpCtx
   | QCSelectAgg !SelOpCtx
   | QCFuncQuery !FuncQOpCtx
   | QCFuncAggQuery !FuncQOpCtx
-  | QCFuncConnection !(Maybe (NonEmpty PGCol)) !FuncQOpCtx
+  | QCFuncConnection !(NonEmpty PGColumnInfo) !FuncQOpCtx
   | QCActionFetch !ActionSelectOpContext
   deriving (Show, Eq)
 
@@ -131,10 +131,16 @@ data ActionSelectOpContext
 -- used in resolvers
 type PGColGNameMap = Map.HashMap G.Name PGColumnInfo
 
+data RelationshipFieldKind
+  = RFKAggregate
+  | RFKSimple
+  | RFKConnection !(NonEmpty PGColumnInfo)
+  deriving (Show, Eq)
+
 data RelationshipField
   = RelationshipField
   { _rfInfo       :: !RelInfo
-  , _rfIsAgg      :: !Bool
+  , _rfIsAgg      :: !RelationshipFieldKind
   , _rfCols       :: !PGColGNameMap
   , _rfPermFilter :: !AnnBoolExpPartialSQL
   , _rfPermLimit  :: !(Maybe Int)
diff --git a/server/src-lib/Hasura/GraphQL/Schema.hs b/server/src-lib/Hasura/GraphQL/Schema.hs
index af1ac0082fd29..46420c6573d53 100644
--- a/server/src-lib/Hasura/GraphQL/Schema.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema.hs
@@ -8,7 +8,7 @@ module Hasura.GraphQL.Schema
   , InsCtx(..)
   , InsCtxMap
   , RelationInfoMap
-  , isAggFld
+  , isAggregateField
   , qualObjectToName
   , ppGCtx
 
@@ -100,16 +100,16 @@ mkPGColGNameMap :: [PGColumnInfo] -> PGColGNameMap
 mkPGColGNameMap cols = Map.fromList $
   flip map cols $ \ci -> (pgiName ci, ci)
 
-numAggOps :: [G.Name]
-numAggOps = [ "sum", "avg", "stddev", "stddev_samp", "stddev_pop"
+numAggregateOps :: [G.Name]
+numAggregateOps = [ "sum", "avg", "stddev", "stddev_samp", "stddev_pop"
             , "variance", "var_samp", "var_pop"
             ]
 
-compAggOps :: [G.Name]
-compAggOps = ["max", "min"]
+compAggregateOps :: [G.Name]
+compAggregateOps = ["max", "min"]
 
-isAggFld :: G.Name -> Bool
-isAggFld = flip elem (numAggOps <> compAggOps)
+isAggregateField :: G.Name -> Bool
+isAggregateField = flip elem (numAggregateOps <> compAggregateOps)
 
 mkComputedFieldFunctionArgSeq :: Seq.Seq FunctionArg -> ComputedFieldFunctionArgSeq
 mkComputedFieldFunctionArgSeq inputArgs =
@@ -225,17 +225,22 @@ mkGCtxRole' tn descM insPermM selPermM updColsM delPermM pkeyCols constraints vi
     mkFldMap ty = Map.fromList . concatMap (mkFld ty)
     mkFld ty = \case
       SFPGColumn ci -> [((ty, pgiName ci), RFPGColumn ci)]
-      SFRelationship (RelationshipFieldInfo relInfo allowAgg cols permFilter permLimit _) ->
+      SFRelationship (RelationshipFieldInfo relInfo allowAgg cols permFilter permLimit maybePkCols _) ->
         let relationshipName = riName relInfo
             relFld = ( (ty, mkRelName relationshipName)
-                     , RFRelationship $ RelationshipField relInfo False cols permFilter permLimit
+                     , RFRelationship $ RelationshipField relInfo RFKSimple cols permFilter permLimit
                      )
             aggRelFld = ( (ty, mkAggRelName relationshipName)
-                        , RFRelationship $ RelationshipField relInfo True cols permFilter permLimit
+                        , RFRelationship $ RelationshipField relInfo RFKAggregate cols permFilter permLimit
                         )
+            maybeConnFld = maybePkCols <&> \pkCols ->
+                           ( (ty, mkConnectionRelName relationshipName)
+                           , RFRelationship $ RelationshipField relInfo
+                             (RFKConnection pkCols) cols permFilter permLimit
+                           )
         in case riType relInfo of
           ObjRel -> [relFld]
-          ArrRel -> bool [relFld] [relFld, aggRelFld] allowAgg
+          ArrRel -> bool [relFld] ([relFld, aggRelFld] <> maybe [] pure maybeConnFld) allowAgg
       SFComputedField cf -> pure
         ( (ty, mkComputedFieldName $ _cfName cf)
         , RFComputedField cf
@@ -269,10 +274,10 @@ mkGCtxRole' tn descM insPermM selPermM updColsM delPermM pkeyCols constraints vi
             numCols = onlyNumCols cols
             compCols = onlyComparableCols cols
             objs = [ mkTableAggObj tn
-                   , mkTableAggFldsObj tn (numCols, numAggOps) (compCols, compAggOps)
-                   ] <> mkColAggFldsObjs selFlds
-            ordByInps = mkTabAggOrdByInpObj tn (numCols, numAggOps) (compCols, compAggOps)
-                        : mkTabAggOpOrdByInpObjs tn (numCols, numAggOps) (compCols, compAggOps)
+                   , mkTableAggregateFieldsObj tn (numCols, numAggregateOps) (compCols, compAggregateOps)
+                   ] <> mkColAggregateFieldsObjs selFlds
+            ordByInps = mkTabAggOrdByInpObj tn (numCols, numAggregateOps) (compCols, compAggregateOps)
+                        : mkTabAggregateOpOrdByInpObjs tn (numCols, numAggregateOps) (compCols, compAggregateOps)
         in (objs, ordByInps)
       _ -> ([], [])
 
@@ -283,13 +288,13 @@ mkGCtxRole' tn descM insPermM selPermM updColsM delPermM pkeyCols constraints vi
     mkTypeMaker "sum" = mkColumnType
     mkTypeMaker _     = onlyFloat
 
-    mkColAggFldsObjs flds =
+    mkColAggregateFieldsObjs flds =
       let numCols = getNumericCols flds
           compCols = getComparableCols flds
-          mkNumObjFld n = mkTableColAggFldsObj tn n (mkTypeMaker n) numCols
-          mkCompObjFld n = mkTableColAggFldsObj tn n mkColumnType compCols
-          numFldsObjs = bool (map mkNumObjFld numAggOps) [] $ null numCols
-          compFldsObjs = bool (map mkCompObjFld compAggOps) [] $ null compCols
+          mkNumObjFld n = mkTableColAggregateFieldsObj tn n (mkTypeMaker n) numCols
+          mkCompObjFld n = mkTableColAggregateFieldsObj tn n mkColumnType compCols
+          numFldsObjs = bool (map mkNumObjFld numAggregateOps) [] $ null numCols
+          compFldsObjs = bool (map mkCompObjFld compAggregateOps) [] $ null compCols
       in numFldsObjs <> compFldsObjs
     -- the fields used in table object
     selObjFldsM = mkFldMap (mkTableTy tn) <$> selFldsM
@@ -349,7 +354,7 @@ getRootFldsRole' tn primaryKey constraints fields funcs insM
         <> funcAggQueries
         <> catMaybes
           [ getSelDet <$> selM
-          , getSelConnectionDet <$> selM
+          , getSelConnectionDet <$> selM <*> maybePrimaryKeyColumns
           , getSelAggDet selM
           , getPKeySelDet <$> selM <*> primaryKey
           ]
@@ -363,13 +368,14 @@ getRootFldsRole' tn primaryKey constraints fields funcs insM
         ]
     }
   where
-    primaryKeyColumn = fmap (fmap pgiColumn . _pkColumns) primaryKey
+    maybePrimaryKeyColumns = fmap _pkColumns primaryKey
     makeFieldMap = mapFromL (_fiName . snd)
     customRootFields = _tcCustomRootFields tableConfig
     colGNameMap = mkPGColGNameMap $ getCols fields
 
     funcQueries = maybe [] getFuncQueryFlds selM
-    funcConnectionQueries = maybe [] getFuncQueryConnectionFlds selM
+    funcConnectionQueries = fromMaybe [] $ getFuncQueryConnectionFlds
+                            <$> selM <*> maybePrimaryKeyColumns
     funcAggQueries = maybe [] getFuncAggQueryFlds selM
 
     mutHelper :: (ViewInfo -> Bool) -> (a -> b) -> Maybe a -> Maybe b
@@ -421,8 +427,9 @@ getRootFldsRole' tn primaryKey constraints fields funcs insM
     selCustName = getCustomNameWith _tcrfSelect
     getSelDet (selFltr, pLimit, hdrs, _) =
       selFldHelper QCSelect (mkSelFld selCustName) selFltr pLimit hdrs
-    getSelConnectionDet (selFltr, pLimit, hdrs, _) =
-      selFldHelper (QCSelectConnection primaryKeyColumn) (mkSelFldConnection Nothing) selFltr pLimit hdrs
+    getSelConnectionDet (selFltr, pLimit, hdrs, _) primaryKeyColumns =
+      selFldHelper (QCSelectConnection primaryKeyColumns)
+      (mkSelFldConnection Nothing) selFltr pLimit hdrs
 
     selAggCustName = getCustomNameWith _tcrfSelectAggregate
     getSelAggDet (Just (selFltr, pLimit, hdrs, True)) =
@@ -445,8 +452,8 @@ getRootFldsRole' tn primaryKey constraints fields funcs insM
     getFuncQueryFlds (selFltr, pLimit, hdrs, _) =
       funcFldHelper QCFuncQuery mkFuncQueryFld selFltr pLimit hdrs
 
-    getFuncQueryConnectionFlds (selFltr, pLimit, hdrs, _) =
-      funcFldHelper (QCFuncConnection primaryKeyColumn) mkFuncQueryConnectionFld selFltr pLimit hdrs
+    getFuncQueryConnectionFlds (selFltr, pLimit, hdrs, _) primaryKeyColumns =
+      funcFldHelper (QCFuncConnection primaryKeyColumns) mkFuncQueryConnectionFld selFltr pLimit hdrs
 
     getFuncAggQueryFlds (selFltr, pLimit, hdrs, True) =
       funcFldHelper QCFuncAggQuery mkFuncAggQueryFld selFltr pLimit hdrs
@@ -496,6 +503,8 @@ getSelPerm tableCache fields role selPermInfo = do
                              , _rfiColumns    = remTableColGNameMap
                              , _rfiPermFilter = spiFilter rmSelPermM
                              , _rfiPermLimit  = spiLimit rmSelPermM
+                             , _rfiPrimaryKeyColumns = _pkColumns <$>
+                                 _tciPrimaryKey (_tiCoreInfo remTableInfo)
                              , _rfiIsNullable = isRelNullable fields relInfo
                              }
 
@@ -608,6 +617,7 @@ mkAdminSelFlds fields tableCache = do
                    , _rfiColumns    = remoteTableColGNameMap
                    , _rfiPermFilter = noFilter
                    , _rfiPermLimit  = Nothing
+                   , _rfiPrimaryKeyColumns = _pkColumns <$> _tciPrimaryKey remoteTableInfo
                    , _rfiIsNullable = isRelNullable fields relInfo
                    }
 
@@ -658,7 +668,7 @@ mkGCtxRole tableCache tn descM fields primaryKey constraints funcs viM tabConfig
     return (ctx, (permCols, icRelations ctx))
   let insPermM = snd <$> tabInsInfoM
       insCtxM = fst <$> tabInsInfoM
-      updColsM = filterColFlds . upiCols <$> _permUpd permInfo
+      updColsM = filterColumnFields . upiCols <$> _permUpd permInfo
       tyAgg = mkGCtxRole' tn descM insPermM selPermM updColsM
               (void $ _permDel permInfo) primaryKey constraints viM funcs
       rootFlds = getRootFldsRole tn primaryKey constraints fields funcs
@@ -668,7 +678,7 @@ mkGCtxRole tableCache tn descM fields primaryKey constraints funcs viM tabConfig
   where
     allCols = getCols fields
     cols = getValidCols fields
-    filterColFlds allowedSet =
+    filterColumnFields allowedSet =
       filter ((`Set.member` allowedSet) . pgiColumn) cols
 
 getRootFldsRole
diff --git a/server/src-lib/Hasura/GraphQL/Schema/Action.hs b/server/src-lib/Hasura/GraphQL/Schema/Action.hs
index f39df90b95d9c..aa874172e1701 100644
--- a/server/src-lib/Hasura/GraphQL/Schema/Action.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/Action.hs
@@ -204,7 +204,7 @@ mkActionFieldsAndTypes actionInfo annotatedOutputType permission =
                         (RelName $ mkNonEmptyTextUnsafe $ coerce relationshipName)
                         (_trType relationship)
                         columnMapping remoteTable True)
-                       False mempty
+                       RFKSimple mempty
                        tableFilter
                        tableLimit
                      )
diff --git a/server/src-lib/Hasura/GraphQL/Schema/Common.hs b/server/src-lib/Hasura/GraphQL/Schema/Common.hs
index bf3ede49f1ce6..c46f327258256 100644
--- a/server/src-lib/Hasura/GraphQL/Schema/Common.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/Common.hs
@@ -13,6 +13,7 @@ module Hasura.GraphQL.Schema.Common
   , mkColumnType
   , mkRelName
   , mkAggRelName
+  , mkConnectionRelName
   , mkComputedFieldName
 
   , mkTableTy
@@ -43,12 +44,13 @@ import           Hasura.SQL.Types
 
 data RelationshipFieldInfo
   = RelationshipFieldInfo
-  { _rfiInfo       :: !RelInfo
-  , _rfiAllowAgg   :: !Bool
-  , _rfiColumns    :: !PGColGNameMap
-  , _rfiPermFilter :: !AnnBoolExpPartialSQL
-  , _rfiPermLimit  :: !(Maybe Int)
-  , _rfiIsNullable :: !Bool
+  { _rfiInfo              :: !RelInfo
+  , _rfiAllowAgg          :: !Bool
+  , _rfiColumns           :: !PGColGNameMap
+  , _rfiPermFilter        :: !AnnBoolExpPartialSQL
+  , _rfiPermLimit         :: !(Maybe Int)
+  , _rfiPrimaryKeyColumns :: !(Maybe (NonEmpty PGColumnInfo))
+  , _rfiIsNullable        :: !Bool
   } deriving (Show, Eq)
 
 data SelField
@@ -82,6 +84,9 @@ mkRelName rn = G.Name $ relNameToTxt rn
 mkAggRelName :: RelName -> G.Name
 mkAggRelName rn = G.Name $ relNameToTxt rn <> "_aggregate"
 
+mkConnectionRelName :: RelName -> G.Name
+mkConnectionRelName rn = G.Name $ relNameToTxt rn <> "_connection"
+
 mkComputedFieldName :: ComputedFieldName -> G.Name
 mkComputedFieldName = G.Name . computedFieldNameToText
 
diff --git a/server/src-lib/Hasura/GraphQL/Schema/OrderBy.hs b/server/src-lib/Hasura/GraphQL/Schema/OrderBy.hs
index cb648dda6c69f..f8e5f9cf35e56 100644
--- a/server/src-lib/Hasura/GraphQL/Schema/OrderBy.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/OrderBy.hs
@@ -3,7 +3,7 @@ module Hasura.GraphQL.Schema.OrderBy
   , ordByEnumTy
   , mkOrdByInpObj
   , mkTabAggOrdByInpObj
-  , mkTabAggOpOrdByInpObjs
+  , mkTabAggregateOpOrdByInpObjs
   ) where
 
 import           Control.Arrow                 ((&&&))
@@ -50,8 +50,8 @@ ordByEnumTy =
         )
       ]
 
-mkTabAggOpOrdByTy :: QualifiedTable -> G.Name -> G.NamedType
-mkTabAggOpOrdByTy tn op =
+mkTabAggregateOpOrdByTy :: QualifiedTable -> G.Name -> G.NamedType
+mkTabAggregateOpOrdByTy tn op =
   G.NamedType $ qualObjectToName tn <> "_" <> op <> "_order_by"
 
 {-
@@ -62,14 +62,14 @@ input table_<op>_order_by {
 }
 -}
 
-mkTabAggOpOrdByInpObjs
+mkTabAggregateOpOrdByInpObjs
   :: QualifiedTable
   -> ([PGColumnInfo], [G.Name])
   -> ([PGColumnInfo], [G.Name])
   -> [InpObjTyInfo]
-mkTabAggOpOrdByInpObjs tn (numCols, numAggOps) (compCols, compAggOps) =
-  mapMaybe (mkInpObjTyM numCols) numAggOps
-  <> mapMaybe (mkInpObjTyM compCols) compAggOps
+mkTabAggregateOpOrdByInpObjs tn (numCols, numAggregateOps) (compCols, compAggregateOps) =
+  mapMaybe (mkInpObjTyM numCols) numAggregateOps
+  <> mapMaybe (mkInpObjTyM compCols) compAggregateOps
   where
 
     mkDesc (G.Name op) =
@@ -77,7 +77,7 @@ mkTabAggOpOrdByInpObjs tn (numCols, numAggOps) (compCols, compAggOps) =
 
     mkInpObjTyM cols op = bool (Just $ mkInpObjTy cols op) Nothing $ null cols
     mkInpObjTy cols op =
-      mkHsraInpTyInfo (Just $ mkDesc op) (mkTabAggOpOrdByTy tn op) $
+      mkHsraInpTyInfo (Just $ mkDesc op) (mkTabAggregateOpOrdByTy tn op) $
       fromInpValL $ map mkColInpVal cols
 
     mkColInpVal ci = InpValInfo Nothing (pgiName ci) Nothing $ G.toGT
@@ -99,17 +99,17 @@ mkTabAggOrdByInpObj
   -> ([PGColumnInfo], [G.Name])
   -> ([PGColumnInfo], [G.Name])
   -> InpObjTyInfo
-mkTabAggOrdByInpObj tn (numCols, numAggOps) (compCols, compAggOps) =
+mkTabAggOrdByInpObj tn (numCols, numAggregateOps) (compCols, compAggregateOps) =
   mkHsraInpTyInfo (Just desc) (mkTabAggOrdByTy tn) $ fromInpValL $
   numOpOrdBys <> compOpOrdBys <> [countInpVal]
   where
     desc = G.Description $
       "order by aggregate values of table " <>> tn
 
-    numOpOrdBys = bool (map mkInpValInfo numAggOps) [] $ null numCols
-    compOpOrdBys = bool (map mkInpValInfo compAggOps) [] $ null compCols
+    numOpOrdBys = bool (map mkInpValInfo numAggregateOps) [] $ null numCols
+    compOpOrdBys = bool (map mkInpValInfo compAggregateOps) [] $ null compCols
     mkInpValInfo op = InpValInfo Nothing op Nothing $ G.toGT $
-                     mkTabAggOpOrdByTy tn op
+                     mkTabAggregateOpOrdByTy tn op
 
     countInpVal = InpValInfo Nothing "count" Nothing $ G.toGT ordByTy
 
@@ -134,14 +134,14 @@ mkOrdByInpObj tn selFlds = (inpObjTy, ordByCtx)
   where
     inpObjTy =
       mkHsraInpTyInfo (Just desc) namedTy $ fromInpValL $
-      map mkColOrdBy pgColFlds <> map mkObjRelOrdBy objRels
-      <> mapMaybe mkArrRelAggOrdBy arrRels
+      map mkColOrdBy pgColumnFields <> map mkObjRelOrdBy objRels
+      <> mapMaybe mkArrayAggregateSelectOrdBy arrRels
 
     namedTy = mkOrdByTy tn
     desc = G.Description $
       "ordering options when selecting data from " <>> tn
 
-    pgColFlds = getPGColumnFields selFlds
+    pgColumnFields = getPGColumnFields selFlds
     relFltr ty = flip filter (getRelationshipFields selFlds) $
                  \rf -> riType (_rfiInfo rf) == ty
     objRels = relFltr ObjRel
@@ -154,7 +154,7 @@ mkOrdByInpObj tn selFlds = (inpObjTy, ordByCtx)
       in InpValInfo Nothing (mkRelName $ riName ri) Nothing $
          G.toGT $ mkOrdByTy $ riRTable ri
 
-    mkArrRelAggOrdBy relationshipField =
+    mkArrayAggregateSelectOrdBy relationshipField =
       let ri = _rfiInfo relationshipField
           isAggAllowed = _rfiAllowAgg relationshipField
           ivi = InpValInfo Nothing (mkAggRelName $ riName ri) Nothing $
@@ -163,7 +163,7 @@ mkOrdByInpObj tn selFlds = (inpObjTy, ordByCtx)
 
     ordByCtx = Map.singleton namedTy $ Map.fromList $
                colOrdBys <> relOrdBys <> arrRelOrdBys
-    colOrdBys = map (pgiName &&& OBIPGCol) pgColFlds
+    colOrdBys = map (pgiName &&& OBIPGCol) pgColumnFields
     relOrdBys = flip map objRels $
                 \relationshipField ->
                   let ri = _rfiInfo relationshipField
@@ -173,7 +173,7 @@ mkOrdByInpObj tn selFlds = (inpObjTy, ordByCtx)
                      )
 
     arrRelOrdBys = flip mapMaybe arrRels $
-                   \(RelationshipFieldInfo ri isAggAllowed colGNameMap fltr _ _) ->
+                   \(RelationshipFieldInfo ri isAggAllowed colGNameMap fltr _ _ _) ->
                      let obItem = ( mkAggRelName $ riName ri
                                   , OBIAgg ri colGNameMap fltr
                                   )
diff --git a/server/src-lib/Hasura/GraphQL/Schema/Select.hs b/server/src-lib/Hasura/GraphQL/Schema/Select.hs
index 5ae4744e86d21..c41d8f7220559 100644
--- a/server/src-lib/Hasura/GraphQL/Schema/Select.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/Select.hs
@@ -2,8 +2,8 @@ module Hasura.GraphQL.Schema.Select
   ( mkTableObj
   , mkTableAggObj
   , mkSelColumnTy
-  , mkTableAggFldsObj
-  , mkTableColAggFldsObj
+  , mkTableAggregateFieldsObj
+  , mkTableColAggregateFieldsObj
   , mkTableEdgeObj
   , mkPageInfoObj
   , mkTableConnectionObj
@@ -45,11 +45,11 @@ mkSelColumnInpTy :: QualifiedTable -> G.NamedType
 mkSelColumnInpTy tn =
   G.NamedType $ qualObjectToName tn <> "_select_column"
 
-mkTableAggFldsTy :: QualifiedTable -> G.NamedType
-mkTableAggFldsTy = addTypeSuffix "_aggregate_fields" . mkTableTy
+mkTableAggregateFieldsTy :: QualifiedTable -> G.NamedType
+mkTableAggregateFieldsTy = addTypeSuffix "_aggregate_fields" . mkTableTy
 
-mkTableColAggFldsTy :: G.Name -> QualifiedTable -> G.NamedType
-mkTableColAggFldsTy op tn =
+mkTableColAggregateFieldsTy :: G.Name -> QualifiedTable -> G.NamedType
+mkTableColAggregateFieldsTy op tn =
   G.NamedType $ qualObjectToName tn <> "_" <> op <> "_fields"
 
 mkTableByPkName :: QualifiedTable -> G.Name
@@ -166,10 +166,11 @@ object_relationship: remote_table
 mkRelationshipField
   :: Bool
   -> RelInfo
+  -> Maybe (NonEmpty PGColumnInfo)
   -> Bool
   -> [ObjFldInfo]
-mkRelationshipField allowAgg (RelInfo rn rTy _ remTab isManual) isNullable = case rTy of
-  ArrRel -> bool [arrRelFld] [arrRelFld, arrConnectionFld, aggArrRelFld] allowAgg
+mkRelationshipField allowAgg (RelInfo rn rTy _ remTab isManual) maybePkCols isNullable = case rTy of
+  ArrRel -> bool [arrRelFld] ([arrRelFld, aggArrRelFld] <> arrConnectionFld) allowAgg
   ObjRel -> [objRelFld]
   where
     objRelFld = mkHsraObjFldInfo (Just "An object relationship")
@@ -183,8 +184,8 @@ mkRelationshipField allowAgg (RelInfo rn rTy _ remTab isManual) isNullable = cas
       (fromInpValL $ mkSelArgs remTab) $
       G.toGT $ G.toNT $ G.toLT $ G.toNT $ mkTableTy remTab
 
-    arrConnectionFld =
-      mkHsraObjFldInfo Nothing (mkRelName rn <> "_connection")
+    arrConnectionFld = if isNothing maybePkCols then [] else pure $
+      mkHsraObjFldInfo Nothing (mkConnectionRelName rn)
       (fromInpValL $ mkConnectionArgs remTab) $
       G.toGT $ G.toNT $ G.toLT $ G.toNT $ mkTableConnectionTy remTab
 
@@ -208,12 +209,12 @@ mkTableObj
 mkTableObj tn descM allowedFlds =
   mkObjTyInfo (Just desc) (mkTableTy tn) Set.empty (mapFromL _fiName flds) TLHasuraType
   where
-    flds = pgColFlds <> relFlds <> computedFlds
-    pgColFlds = map mkPGColFld $ getPGColumnFields allowedFlds
+    flds = pgColumnFields <> relFlds <> computedFlds
+    pgColumnFields = map mkPGColFld $ getPGColumnFields allowedFlds
     relFlds = concatMap mkRelationshipField' $ getRelationshipFields allowedFlds
     computedFlds = map mkComputedFieldFld $ getComputedFields allowedFlds
-    mkRelationshipField' (RelationshipFieldInfo relInfo allowAgg _ _ _ isNullable) =
-      mkRelationshipField allowAgg relInfo isNullable
+    mkRelationshipField' (RelationshipFieldInfo relInfo allowAgg _ _ _ maybePkCols isNullable) =
+      mkRelationshipField allowAgg relInfo maybePkCols isNullable
     desc = mkDescriptionWith descM $ "columns and relationships of " <>> tn
 
 {-
@@ -232,7 +233,7 @@ mkTableAggObj tn =
       "aggregated selection of " <>> tn
 
     aggFld = mkHsraObjFldInfo Nothing "aggregate" Map.empty $ G.toGT $
-             mkTableAggFldsTy tn
+             mkTableAggregateFieldsTy tn
     nodesFld = mkHsraObjFldInfo Nothing "nodes" Map.empty $ G.toGT $
                G.toNT $ G.toLT $ G.toNT $ mkTableTy tn
 
@@ -249,13 +250,13 @@ type table_aggregate_fields{
   min: table_min_fields
 }
 -}
-mkTableAggFldsObj
+mkTableAggregateFieldsObj
   :: QualifiedTable
   -> ([PGColumnInfo], [G.Name])
   -> ([PGColumnInfo], [G.Name])
   -> ObjTyInfo
-mkTableAggFldsObj tn (numCols, numAggOps) (compCols, compAggOps) =
-  mkHsraObjTyInfo (Just desc) (mkTableAggFldsTy tn) Set.empty $ mapFromL _fiName $
+mkTableAggregateFieldsObj tn (numCols, numAggregateOps) (compCols, compAggregateOps) =
+  mkHsraObjTyInfo (Just desc) (mkTableAggregateFieldsTy tn) Set.empty $ mapFromL _fiName $
   countFld : (numFlds <> compFlds)
   where
     desc = G.Description $
@@ -271,11 +272,11 @@ mkTableAggFldsObj tn (numCols, numAggOps) (compCols, compAggOps) =
     distinctInpVal = InpValInfo Nothing "distinct" Nothing $ G.toGT $
                      mkScalarTy PGBoolean
 
-    numFlds = bool (map mkColOpFld numAggOps) [] $ null numCols
-    compFlds = bool (map mkColOpFld compAggOps) [] $ null compCols
+    numFlds = bool (map mkColumnOpFld numAggregateOps) [] $ null numCols
+    compFlds = bool (map mkColumnOpFld compAggregateOps) [] $ null compCols
 
-    mkColOpFld op = mkHsraObjFldInfo Nothing op Map.empty $ G.toGT $
-                    mkTableColAggFldsTy op tn
+    mkColumnOpFld op = mkHsraObjFldInfo Nothing op Map.empty $ G.toGT $
+                    mkTableColAggregateFieldsTy op tn
 
 {-
 type table_<agg-op>_fields{
@@ -284,14 +285,14 @@ type table_<agg-op>_fields{
    .        .
 }
 -}
-mkTableColAggFldsObj
+mkTableColAggregateFieldsObj
   :: QualifiedTable
   -> G.Name
   -> (PGColumnType -> G.NamedType)
   -> [PGColumnInfo]
   -> ObjTyInfo
-mkTableColAggFldsObj tn op f cols =
-  mkHsraObjTyInfo (Just desc) (mkTableColAggFldsTy op tn) Set.empty $ mapFromL _fiName $
+mkTableColAggregateFieldsObj tn op f cols =
+  mkHsraObjTyInfo (Just desc) (mkTableColAggregateFieldsTy op tn) Set.empty $ mapFromL _fiName $
   map mkColObjFld cols
   where
     desc = G.Description $ "aggregate " <> G.unName op <> " on columns"
diff --git a/server/src-lib/Hasura/RQL/DML/Mutation.hs b/server/src-lib/Hasura/RQL/DML/Mutation.hs
index 9438880a09f2b..bd75e3582bcfc 100644
--- a/server/src-lib/Hasura/RQL/DML/Mutation.hs
+++ b/server/src-lib/Hasura/RQL/DML/Mutation.hs
@@ -70,7 +70,7 @@ mutateAndFetchCols qt cols (cte, p) strfyNum =
     tabFrom = FromIden aliasIden
     tabPerm = TablePerm annBoolExpTrue Nothing
     selFlds = flip map cols $
-              \ci -> (fromPGCol $ pgiColumn ci, mkAnnColFieldAsText ci)
+              \ci -> (fromPGCol $ pgiColumn ci, mkAnnColumnFieldAsText ci)
 
     sql = toSQL selectWith
     selectWith = S.SelectWith [(S.Alias aliasIden, cte)] select
@@ -86,7 +86,7 @@ mutateAndFetchCols qt cols (cte, p) strfyNum =
       , S.selFrom = Just $ S.FromExp [S.FIIden aliasIden]
       }
     colSel = S.SESelect $ mkSQLSelect JASMultipleRows $
-             AnnSelG selFlds tabFrom tabPerm noTableArgs strfyNum
+             AnnSelectG selFlds tabFrom tabPerm noSelectArgs strfyNum
 
 -- | Note:- Using sorted columns is necessary to enable casting the rows returned by VALUES expression to table type.
 -- For example, let's consider the table, `CREATE TABLE test (id serial primary key, name text not null, age int)`.
diff --git a/server/src-lib/Hasura/RQL/DML/Returning.hs b/server/src-lib/Hasura/RQL/DML/Returning.hs
index 344fc79426a43..cb4f112ff2794 100644
--- a/server/src-lib/Hasura/RQL/DML/Returning.hs
+++ b/server/src-lib/Hasura/RQL/DML/Returning.hs
@@ -12,7 +12,7 @@ import qualified Hasura.SQL.DML          as S
 data MutFldG v
   = MCount
   | MExp !T.Text
-  | MRet !(AnnFldsG v)
+  | MRet !(AnnFieldsG v)
   deriving (Show, Eq)
 
 traverseMutFld
@@ -23,7 +23,7 @@ traverseMutFld
 traverseMutFld f = \case
   MCount    -> pure MCount
   MExp t    -> pure $ MExp t
-  MRet flds -> MRet <$> traverse (traverse (traverseAnnFld f)) flds
+  MRet flds -> MRet <$> traverse (traverse (traverseAnnField f)) flds
 
 type MutFld = MutFldG S.SQLExp
 
@@ -31,7 +31,7 @@ type MutFldsG v = Fields (MutFldG v)
 
 data MutationOutputG v
   = MOutMultirowFields !(MutFldsG v)
-  | MOutSinglerowObject !(AnnFldsG v)
+  | MOutSinglerowObject !(AnnFieldsG v)
   deriving (Show, Eq)
 
 traverseMutationOutput
@@ -42,7 +42,7 @@ traverseMutationOutput f = \case
   MOutMultirowFields mutationFields ->
     MOutMultirowFields <$> traverse (traverse (traverseMutFld f)) mutationFields
   MOutSinglerowObject annFields ->
-    MOutSinglerowObject <$> traverseAnnFlds f annFields
+    MOutSinglerowObject <$> traverseAnnFields f annFields
 
 type MutationOutput = MutationOutputG S.SQLExp
 
@@ -59,15 +59,15 @@ type MutFlds = MutFldsG S.SQLExp
 hasNestedFld :: MutationOutputG a -> Bool
 hasNestedFld = \case
   MOutMultirowFields flds -> any isNestedMutFld flds
-  MOutSinglerowObject annFlds -> any isNestedAnnFld annFlds
+  MOutSinglerowObject annFlds -> any isNestedAnnField annFlds
   where
     isNestedMutFld (_, mutFld) = case mutFld of
-      MRet annFlds -> any isNestedAnnFld annFlds
+      MRet annFlds -> any isNestedAnnField annFlds
       _            -> False
-    isNestedAnnFld (_, annFld) = case annFld of
-      FObj _ -> True
-      FArr _ -> True
-      _      -> False
+    isNestedAnnField (_, annFld) = case annFld of
+      AFObjectRelation _ -> True
+      AFArrayRelation _  -> True
+      _                  -> False
 
 pgColsFromMutFld :: MutFld -> [(PGCol, PGColumnType)]
 pgColsFromMutFld = \case
@@ -75,16 +75,16 @@ pgColsFromMutFld = \case
   MExp _ -> []
   MRet selFlds ->
     flip mapMaybe selFlds $ \(_, annFld) -> case annFld of
-    FCol (AnnColField (PGColumnInfo col _ _ colTy _ _) _ _) -> Just (col, colTy)
-    _                                                       -> Nothing
+    AFColumn (AnnColumnField (PGColumnInfo col _ _ colTy _ _) _ _) -> Just (col, colTy)
+    _                                                              -> Nothing
 
 pgColsFromMutFlds :: MutFlds -> [(PGCol, PGColumnType)]
 pgColsFromMutFlds = concatMap (pgColsFromMutFld . snd)
 
-pgColsToSelFlds :: [PGColumnInfo] -> [(FieldName, AnnFld)]
+pgColsToSelFlds :: [PGColumnInfo] -> [(FieldName, AnnField)]
 pgColsToSelFlds cols =
   flip map cols $
-  \pgColInfo -> (fromPGCol $ pgiColumn pgColInfo, mkAnnColField pgColInfo Nothing)
+  \pgColInfo -> (fromPGCol $ pgiColumn pgColInfo, mkAnnColumnField pgColInfo Nothing)
 
 mkDefaultMutFlds :: Maybe [PGColumnInfo] -> MutationOutput
 mkDefaultMutFlds = MOutMultirowFields . \case
@@ -107,7 +107,7 @@ mkMutFldExp cteAlias preCalAffRows strfyNum = \case
     let tabFrom = FromIden cteAlias
         tabPerm = TablePerm annBoolExpTrue Nothing
     in S.SESelect $ mkSQLSelect JASMultipleRows $
-       AnnSelG selFlds tabFrom tabPerm noTableArgs strfyNum
+       AnnSelectG selFlds tabFrom tabPerm noSelectArgs strfyNum
 
 {- Note [Mutation output expression]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -171,7 +171,7 @@ mkMutationOutputExp qt allCols preCalAffRows cte mutOutput strfyNum =
                 let tabFrom = FromIden allColumnsAlias
                     tabPerm = TablePerm annBoolExpTrue Nothing
                 in S.SESelect $ mkSQLSelect JASSingleObject $
-                   AnnSelG annFlds tabFrom tabPerm noTableArgs strfyNum
+                   AnnSelectG annFlds tabFrom tabPerm noSelectArgs strfyNum
 
 
 checkRetCols
diff --git a/server/src-lib/Hasura/RQL/DML/Select.hs b/server/src-lib/Hasura/RQL/DML/Select.hs
index ab8a892b435b2..abfc34f8f34e0 100644
--- a/server/src-lib/Hasura/RQL/DML/Select.hs
+++ b/server/src-lib/Hasura/RQL/DML/Select.hs
@@ -105,7 +105,7 @@ convOrderByElem
   => SessVarBldr m
   -> (FieldInfoMap FieldInfo, SelPermInfo)
   -> OrderByCol
-  -> m AnnObCol
+  -> m (AnnOrderByElement S.SQLExp)
 convOrderByElem sessVarBldr (flds, spi) = \case
   OCPG fldName -> do
     fldInfo <- askFieldInfo flds fldName
@@ -118,7 +118,7 @@ convOrderByElem sessVarBldr (flds, spi) = \case
            [ fldName <<> " has type 'geometry'"
            , " and cannot be used in order_by"
            ]
-          else return $ AOCPG $ pgiColumn colInfo
+          else return $ AOCColumn colInfo
       FIRelationship _ -> throw400 UnexpectedPayload $ mconcat
         [ fldName <<> " is a"
         , " relationship and should be expanded"
@@ -146,7 +146,7 @@ convOrderByElem sessVarBldr (flds, spi) = \case
           ]
         (relFim, relSpi) <- fetchRelDet (riName relInfo) (riRTable relInfo)
         resolvedSelFltr <- convAnnBoolExpPartialSQL sessVarBldr $ spiFilter relSpi
-        AOCObj relInfo resolvedSelFltr <$>
+        AOCObjectRelation relInfo resolvedSelFltr <$>
           convOrderByElem sessVarBldr (relFim, relSpi) rest
 
 convSelectQ
@@ -163,12 +163,12 @@ convSelectQ fieldInfoMap selPermInfo selQ sessVarBldr prepValBldr = do
     indexedForM (sqColumns selQ) $ \case
     (ECSimple pgCol) -> do
       colInfo <- convExtSimple fieldInfoMap selPermInfo pgCol
-      return (fromPGCol pgCol, mkAnnColField colInfo Nothing)
+      return (fromPGCol pgCol, mkAnnColumnField colInfo Nothing)
     (ECRel relName mAlias relSelQ) -> do
       annRel <- convExtRel fieldInfoMap relName mAlias
                 relSelQ sessVarBldr prepValBldr
       return ( fromRel $ fromMaybe relName mAlias
-             , either FObj FArr annRel
+             , either AFObjectRelation AFArrayRelation annRel
              )
 
   -- let spiT = spiTable selPermInfo
@@ -193,11 +193,11 @@ convSelectQ fieldInfoMap selPermInfo selQ sessVarBldr prepValBldr = do
 
   let tabFrom = FromTable $ spiTable selPermInfo
       tabPerm = TablePerm resolvedSelFltr mPermLimit
-      tabArgs = TableArgs wClause annOrdByM mQueryLimit
+      tabArgs = SelectArgs wClause annOrdByM mQueryLimit
                 (S.intToSQLExp <$> mQueryOffset) Nothing
 
   strfyNum <- stringifyNum <$> askSQLGenCtx
-  return $ AnnSelG annFlds tabFrom tabPerm tabArgs strfyNum
+  return $ AnnSelectG annFlds tabFrom tabPerm tabArgs strfyNum
 
   where
     mQueryOffset = sqOffset selQ
@@ -224,7 +224,7 @@ convExtRel
   -> SelectQExt
   -> SessVarBldr m
   -> (PGColumnType -> Value -> m S.SQLExp)
-  -> m (Either ObjSel ArrSel)
+  -> m (Either ObjectRelationSelect ArraySelect)
 convExtRel fieldInfoMap relName mAlias selQ sessVarBldr prepValBldr = do
   -- Point to the name key
   relInfo <- withPathK "name" $
@@ -235,9 +235,9 @@ convExtRel fieldInfoMap relName mAlias selQ sessVarBldr prepValBldr = do
   case relTy of
     ObjRel -> do
       when misused $ throw400 UnexpectedPayload objRelMisuseMsg
-      return $ Left $ AnnRelG (fromMaybe relName mAlias) colMapping annSel
+      return $ Left $ AnnRelationSelectG (fromMaybe relName mAlias) colMapping annSel
     ArrRel ->
-      return $ Right $ ASSimple $ AnnRelG (fromMaybe relName mAlias)
+      return $ Right $ ASSimple $ AnnRelationSelectG (fromMaybe relName mAlias)
                colMapping annSel
   where
     pgWhenRelErr = "only relationships can be expanded"
@@ -278,9 +278,9 @@ selectQuerySQL :: JsonAggSelect -> AnnSimpleSel -> Q.Query
 selectQuerySQL jsonAggSelect sel =
   Q.fromBuilder $ toSQL $ mkSQLSelect jsonAggSelect sel
 
-selectAggQuerySQL :: AnnAggSel -> Q.Query
+selectAggQuerySQL :: AnnAggregateSelect -> Q.Query
 selectAggQuerySQL =
-  Q.fromBuilder . toSQL . mkAggSelect
+  Q.fromBuilder . toSQL . mkAggregateSelect
 
 asSingleRowJsonResp :: Q.Query -> [Q.PrepArg] -> Q.TxE QErr EncJSON
 asSingleRowJsonResp query args =
diff --git a/server/src-lib/Hasura/RQL/DML/Select/Internal.hs b/server/src-lib/Hasura/RQL/DML/Select/Internal.hs
index cc8a1cca362de..d0da79673ca6c 100644
--- a/server/src-lib/Hasura/RQL/DML/Select/Internal.hs
+++ b/server/src-lib/Hasura/RQL/DML/Select/Internal.hs
@@ -1,16 +1,13 @@
 module Hasura.RQL.DML.Select.Internal
   ( mkSQLSelect
-  , mkAggSelect
-  -- , mkConnectionSelect
-  -- , JoinCandidate(..)
+  , mkAggregateSelect
   , mkConnectionSelect
   , module Hasura.RQL.DML.Select.Types
   )
 where
 
-import           Control.Lens                hiding (op)
+import           Control.Lens
 import           Control.Monad.Writer.Strict
-import           Data.List                   (delete, sort)
 import           Instances.TH.Lift           ()
 
 import qualified Data.HashMap.Strict         as HM
@@ -22,7 +19,7 @@ import           Hasura.RQL.DML.Internal
 import           Hasura.RQL.DML.Select.Types
 import           Hasura.RQL.GBoolExp
 import           Hasura.RQL.Types
-import           Hasura.SQL.Rewrite          (prefixNumToAliases)
+import           Hasura.SQL.Rewrite
 import           Hasura.SQL.Types
 
 import qualified Hasura.SQL.DML              as S
@@ -34,8 +31,8 @@ import qualified Hasura.SQL.DML              as S
 functionToIden :: QualifiedFunction -> Iden
 functionToIden = Iden . qualObjectToText
 
-selFromToFromItem :: Iden -> SelectFrom -> S.FromItem
-selFromToFromItem pfx = \case
+selectFromToFromItem :: Iden -> SelectFrom -> S.FromItem
+selectFromToFromItem pfx = \case
   FromTable tn -> S.FISimple tn Nothing
   FromIden i   -> S.FIIden i
   FromFunction qf args defListM ->
@@ -44,17 +41,17 @@ selFromToFromItem pfx = \case
 
 -- This function shouldn't be present ideally
 -- You should be able to retrieve this information
--- from the FromItem generated with selFromToFromItem
+-- from the FromItem generated with selectFromToFromItem
 -- however given from S.FromItem is modelled, it is not
 -- possible currently
-selFromToQual :: SelectFrom -> S.Qual
-selFromToQual = \case
+selectFromToQual :: SelectFrom -> S.Qual
+selectFromToQual = \case
   FromTable tn         -> S.QualTable tn
   FromIden i           -> S.QualIden i Nothing
   FromFunction qf _ _  -> S.QualIden (functionToIden qf) Nothing
 
-aggFldToExp :: AggFlds -> S.SQLExp
-aggFldToExp aggFlds = jsonRow
+aggregateFieldToExp :: AggregateFields -> S.SQLExp
+aggregateFieldToExp aggFlds = jsonRow
   where
     jsonRow = S.applyJsonBuildObj (concatMap aggToFlds aggFlds)
     withAls fldName sqlExp = [S.SELit fldName, sqlExp]
@@ -63,26 +60,16 @@ aggFldToExp aggFlds = jsonRow
       AFOp aggOp  -> aggOpToObj aggOp
       AFExp e     -> S.SELit e
 
-    aggOpToObj (AggOp op flds) =
-      S.applyJsonBuildObj $ concatMap (colFldsToExtr op) flds
+    aggOpToObj (AggregateOp opText flds) =
+      S.applyJsonBuildObj $ concatMap (colFldsToExtr opText) flds
 
-    colFldsToExtr op (FieldName t, PCFCol col) =
+    colFldsToExtr opText (FieldName t, PCFCol col) =
       [ S.SELit t
-      , S.SEFnApp op [S.SEIden $ toIden col] Nothing
+      , S.SEFnApp opText [S.SEIden $ toIden col] Nothing
       ]
     colFldsToExtr _ (FieldName t, PCFExp e) =
       [ S.SELit t , S.SELit e]
 
-arrNodeToSelect :: BaseNode -> [S.Extractor] -> S.BoolExp -> S.Select
-arrNodeToSelect bn extrs joinCond =
-  S.mkSelect
-    { S.selExtr = extrs
-    , S.selFrom = Just $ S.FromExp [selFrom]
-    }
-  where
-    selFrom = S.mkSelFromItem (baseNodeToSel joinCond bn) $ S.Alias $
-              _bnPrefix bn
-
 asSingleRowExtr :: S.Alias -> S.SQLExp
 asSingleRowExtr col =
   S.SEFnApp "coalesce" [jsonAgg, S.SELit "null"] Nothing
@@ -93,11 +80,12 @@ asSingleRowExtr col =
               ]
 
 withJsonAggExtr
-  :: Bool -> Maybe Int -> Maybe S.OrderByExp -> S.Alias -> S.SQLExp
-withJsonAggExtr subQueryReq permLimitM ordBy alias =
+  :: PermissionLimitSubQuery -> Maybe S.OrderByExp -> S.Alias -> S.SQLExp
+withJsonAggExtr permLimitSubQuery ordBy alias =
   -- if select has aggregations then use subquery to apply permission limit
-  if subQueryReq then maybe simpleJsonAgg withPermLimit permLimitM
-  else simpleJsonAgg
+  case permLimitSubQuery of
+    PLSQRequired permLimit -> withPermLimit permLimit
+    PLSQNotRequired        -> simpleJsonAgg
   where
     simpleJsonAgg = mkSimpleJsonAgg rowIdenExp ordBy
     rowIdenExp = S.SEIden $ S.getAlias alias
@@ -111,7 +99,7 @@ withJsonAggExtr subQueryReq permLimitM ordBy alias =
     withPermLimit limit =
       let subSelect = mkSubSelect limit
           rowIden = S.mkQIdenExp subSelAls alias
-          extr = S.Extractor (mkSimpleJsonAgg rowIden newOrdBy) Nothing
+          extr = S.Extractor (mkSimpleJsonAgg rowIden newOrderBy) Nothing
           fromExp = S.FromExp $ pure $
                     S.mkSelFromItem subSelect $ S.Alias subSelAls
       in S.SESelect $ S.mkSelect { S.selExtr = pure extr
@@ -126,7 +114,7 @@ withJsonAggExtr subQueryReq permLimitM ordBy alias =
       in S.mkSelect { S.selExtr    = jsonRowExtr : obExtrs
                     , S.selFrom    = Just $ S.FromExp $ pure unnestFromItem
                     , S.selLimit   = Just $ S.LimitExp $ S.intToSQLExp limit
-                    , S.selOrderBy = newOrdBy
+                    , S.selOrderBy = newOrderBy
                     }
 
     unnestFromItem =
@@ -135,11 +123,11 @@ withJsonAggExtr subQueryReq permLimitM ordBy alias =
       in S.FIUnnest arrayAggItems (S.Alias unnestTable) $
          rowIdenExp : map S.SEIden newOBAliases
 
-    newOrdBy = bool (Just $ S.OrderByExp newOBItems) Nothing $ null newOBItems
+    newOrderBy = S.OrderByExp <$> NE.nonEmpty newOBItems
 
-    (newOBItems, obCols, newOBAliases) = maybe ([], [], []) transformOrdBy ordBy
-    transformOrdBy (S.OrderByExp l) = unzip3 $
-      flip map (zip l [1..]) $ \(obItem, i::Int) ->
+    (newOBItems, obCols, newOBAliases) = maybe ([], [], []) transformOrderBy ordBy
+    transformOrderBy (S.OrderByExp l) = unzip3 $
+      flip map (zip (toList l) [1..]) $ \(obItem, i::Int) ->
                  let iden = Iden $ "ob_col_" <> T.pack (show i)
                  in ( obItem{S.oColumn = S.SEIden iden}
                     , S.oColumn obItem
@@ -147,112 +135,81 @@ withJsonAggExtr subQueryReq permLimitM ordBy alias =
                     )
 
 asJsonAggExtr
-  :: JsonAggSelect -> S.Alias -> Bool -> Maybe Int -> Maybe S.OrderByExp -> S.Extractor
-asJsonAggExtr jsonAggSelect als subQueryReq permLimit ordByExpM =
+  :: JsonAggSelect -> S.Alias -> PermissionLimitSubQuery -> Maybe S.OrderByExp -> S.Extractor
+asJsonAggExtr jsonAggSelect als permLimitSubQuery ordByExpM =
   flip S.Extractor (Just als) $ case jsonAggSelect of
-    JASMultipleRows -> withJsonAggExtr subQueryReq permLimit ordByExpM als
+    JASMultipleRows -> withJsonAggExtr permLimitSubQuery ordByExpM als
     JASSingleObject -> asSingleRowExtr als
 
 -- array relationships are not grouped, so have to be prefixed by
 -- parent's alias
-mkUniqArrRelAls :: FieldName -> [FieldName] -> Iden
-mkUniqArrRelAls parAls flds =
-  Iden $
-  getFieldNameTxt parAls <> "."
-  <> T.intercalate "." (map getFieldNameTxt flds)
-
-mkArrRelTableAls :: Iden -> FieldName -> [FieldName] -> Iden
-mkArrRelTableAls pfx parAls flds =
+mkUniqArrayRelationAlias :: FieldName -> [FieldName] -> Iden
+mkUniqArrayRelationAlias parAls flds =
+  let sortedFields = sort flds
+  in Iden $
+     getFieldNameTxt parAls <> "."
+     <> T.intercalate "." (map getFieldNameTxt sortedFields)
+
+mkArrayRelationTableAlias :: Iden -> FieldName -> [FieldName] -> Iden
+mkArrayRelationTableAlias pfx parAls flds =
   pfx <> Iden ".ar." <> uniqArrRelAls
   where
-    uniqArrRelAls = mkUniqArrRelAls parAls flds
+    uniqArrRelAls = mkUniqArrayRelationAlias parAls flds
 
-mkObjRelTableAls :: Iden -> RelName -> Iden
-mkObjRelTableAls pfx relName =
+mkObjectRelationTableAlias :: Iden -> RelName -> Iden
+mkObjectRelationTableAlias pfx relName =
   pfx <> Iden ".or." <> toIden relName
 
-mkComputedFieldTableAls :: Iden -> FieldName -> Iden
-mkComputedFieldTableAls pfx fldAls =
+mkComputedFieldTableAlias :: Iden -> FieldName -> Iden
+mkComputedFieldTableAlias pfx fldAls =
   pfx <> Iden ".cf." <> toIden fldAls
 
-mkBaseTableAls :: Iden -> Iden
-mkBaseTableAls pfx =
+mkBaseTableAlias :: Iden -> Iden
+mkBaseTableAlias pfx =
   pfx <> Iden ".base"
 
-mkBaseTableColAls :: Iden -> PGCol -> Iden
-mkBaseTableColAls pfx pgColumn =
+mkBaseTableColumnAlias :: Iden -> PGCol -> Iden
+mkBaseTableColumnAlias pfx pgColumn =
   pfx <> Iden ".pg." <> toIden pgColumn
 
 mkOrderByFieldName :: RelName -> FieldName
 mkOrderByFieldName relName =
   FieldName $ relNameToTxt relName <> "." <> "order_by"
 
+mkAggregateOrderByAlias :: AnnAggregateOrderBy -> S.Alias
+mkAggregateOrderByAlias = (S.Alias . Iden) . \case
+  AAOCount -> "count"
+  AAOOp opText col -> opText <> "." <> getPGColTxt (pgiColumn col)
+
+mkArrayRelationSourcePrefix
+  :: Iden
+  -> FieldName
+  -> HM.HashMap FieldName [FieldName]
+  -> FieldName
+  -> Iden
+mkArrayRelationSourcePrefix parentSourcePrefix parentFieldName similarFieldsMap fieldName =
+  mkArrayRelationTableAlias parentSourcePrefix parentFieldName $
+  HM.lookupDefault [fieldName] fieldName similarFieldsMap
+
+mkArrayRelationAlias
+  :: FieldName
+  -> HM.HashMap FieldName [FieldName]
+  -> FieldName
+  -> S.Alias
+mkArrayRelationAlias parentFieldName similarFieldsMap fieldName =
+  S.Alias $ mkUniqArrayRelationAlias parentFieldName $
+  HM.lookupDefault [fieldName] fieldName similarFieldsMap
+
 fromTableRowArgs
   :: Iden -> FunctionArgsExpTableRow S.SQLExp -> S.FunctionArgs
 fromTableRowArgs pfx = toFunctionArgs . fmap toSQLExp
   where
     toFunctionArgs (FunctionArgsExp positional named) =
       S.FunctionArgs positional named
-    toSQLExp (AETableRow Nothing)    = S.SERowIden $ mkBaseTableAls pfx
-    toSQLExp (AETableRow (Just acc)) = S.mkQIdenExp (mkBaseTableAls pfx) acc
+    toSQLExp (AETableRow Nothing)    = S.SERowIden $ mkBaseTableAlias pfx
+    toSQLExp (AETableRow (Just acc)) = S.mkQIdenExp (mkBaseTableAlias pfx) acc
     toSQLExp (AEInput s)             = s
 
--- posttgres ignores anything beyond 63 chars for an iden
--- in this case, we'll need to use json_build_object function
--- json_build_object is slower than row_to_json hence it is only
--- used when needed
-buildJsonObject
-  :: Iden -> FieldName -> ArrRelCtx -> Bool
-  -> [(FieldName, AnnFld)] -> (S.Alias, S.SQLExp)
-buildJsonObject pfx parAls arrRelCtx strfyNum flds =
-  if any ( (> 63) . T.length . getFieldNameTxt . fst ) flds
-  then withJsonBuildObj parAls jsonBuildObjExps
-  else withRowToJSON parAls rowToJsonExtrs
-  where
-    jsonBuildObjExps = concatMap (toSQLFld withAlsExp) flds
-    rowToJsonExtrs = map (toSQLFld withAlsExtr) flds
-
-    withAlsExp fldName sqlExp =
-      [S.SELit $ getFieldNameTxt fldName, sqlExp]
-
-    withAlsExtr fldName sqlExp =
-      S.Extractor sqlExp $ Just $ S.toAlias fldName
-
-    toSQLFld :: (FieldName -> S.SQLExp -> f)
-             -> (FieldName, AnnFld) -> f
-    toSQLFld f (fldAls, fld) = f fldAls $ case fld of
-      FCol c      -> toSQLCol c
-      FExp e      -> S.SELit e
-      FObj objSel ->
-        let qual = mkObjRelTableAls pfx $ aarName objSel
-        in S.mkQIdenExp qual fldAls
-      FArr arrSel      ->
-        let arrPfx = _aniPrefix $ mkArrNodeInfo pfx parAls arrRelCtx $
-                                  ANIField (fldAls, arrSel)
-        in S.mkQIdenExp arrPfx fldAls
-      FComputedField (CFSScalar computedFieldScalar) ->
-        fromScalarComputedField computedFieldScalar
-      FComputedField (CFSTable _ _) ->
-        let ccPfx = mkComputedFieldTableAls pfx fldAls
-        in S.mkQIdenExp ccPfx fldAls
-
-    toSQLCol :: AnnColField -> S.SQLExp
-    toSQLCol (AnnColField col asText colOpM) =
-      toJSONableExp strfyNum (pgiType col) asText $ withColOp colOpM $
-      S.mkQIdenExp (mkBaseTableAls pfx) $ pgiColumn col
-
-    fromScalarComputedField :: ComputedFieldScalarSel S.SQLExp -> S.SQLExp
-    fromScalarComputedField computedFieldScalar =
-      toJSONableExp strfyNum (PGColumnScalar ty) False $ withColOp colOpM $
-      S.SEFunction $ S.FunctionExp fn (fromTableRowArgs pfx args) Nothing
-      where
-        ComputedFieldScalarSel fn args ty colOpM = computedFieldScalar
-
-    withColOp :: Maybe ColOp -> S.SQLExp -> S.SQLExp
-    withColOp colOpM sqlExp = case colOpM of
-      Nothing              -> sqlExp
-      Just (ColOp op cExp) -> S.mkSQLOpExp op sqlExp cExp
-
 -- uses row_to_json to build a json object
 withRowToJSON
   :: FieldName -> [S.Extractor] -> (S.Alias, S.SQLExp)
@@ -269,440 +226,575 @@ withJsonBuildObj parAls exps =
   where
     jsonRow = S.applyJsonBuildObj exps
 
-mkAggObFld :: AnnAggOrdBy -> FieldName
-mkAggObFld = \case
-  AAOCount     -> FieldName "count"
-  AAOOp op col -> FieldName $ op <> "." <> getPGColTxt col
-
-mkAggObExtrAndFlds :: AnnAggOrdBy -> (S.Extractor, AggFlds)
-mkAggObExtrAndFlds annAggOb = case annAggOb of
-  AAOCount       ->
-    ( S.Extractor S.countStar als
-    , [(FieldName "count", AFCount S.CTStar)]
-    )
-  AAOOp op pgColumn ->
-    ( S.Extractor (S.SEFnApp op [S.SEIden $ toIden pgColumn] Nothing) als
-    , [(FieldName op, AFOp $ AggOp op [(fromPGCol pgColumn, PCFCol pgColumn)])]
-    )
+mkAggregateOrderByExtractorAndFields
+  :: AnnAggregateOrderBy -> (S.Extractor, AggregateFields)
+mkAggregateOrderByExtractorAndFields annAggOrderBy =
+  case annAggOrderBy of
+    AAOCount       ->
+      ( S.Extractor S.countStar alias
+      , [(FieldName "count", AFCount S.CTStar)]
+      )
+    AAOOp opText pgColumnInfo ->
+      let pgColumn = pgiColumn pgColumnInfo
+      in ( S.Extractor (S.SEFnApp opText [S.SEIden $ toIden pgColumn] Nothing) alias
+         , [(FieldName opText, AFOp $ AggregateOp opText [(fromPGCol pgColumn, PCFCol pgColumn)])]
+         )
   where
-    als = Just $ S.toAlias $ mkAggObFld annAggOb
-
-processAnnOrderByItem
-  :: Iden
-  -> FieldName
-  -> ArrRelCtx
-  -> Bool
-  -> AnnOrderByItem
-       -- the extractors which will select the needed columns
-  -> ( (S.Alias, S.SQLExp)
-       -- the sql order by item that is attached to the final select
-     , S.OrderByItem
-       -- extra nodes for order by
-     , OrderByNode
-     )
-processAnnOrderByItem pfx parAls arrRelCtx strfyNum obItemG =
-  ( (obColAls, obColExp)
-  , sqlOrdByItem
-  , relNodeM
-  )
-  where
-    OrderByItemG obTyM annObCol obNullsM = obItemG
-    ((obColAls, obColExp), relNodeM) =
-      processAnnOrderByCol pfx parAls arrRelCtx strfyNum annObCol
-
-    sqlOrdByItem =
-      S.OrderByItem (S.SEIden $ toIden obColAls)
-      (unOrderType <$> obTyM) (unNullsOrder <$> obNullsM)
-
-processAnnOrderByCol
-  :: Iden
-  -> FieldName
-  -> ArrRelCtx
-  -> Bool
-  -> AnnObCol
-       -- the extractors which will select the needed columns
-  -> ( (S.Alias, S.SQLExp)
-       -- extra nodes for order by
-     , OrderByNode
-     )
-processAnnOrderByCol pfx parAls arrRelCtx strfyNum = \case
-  AOCPG pgColumn ->
-    let
-      qualCol  = S.mkQIdenExp (mkBaseTableAls pfx) (toIden pgColumn)
-      obColAls = mkBaseTableColAls pfx pgColumn
-    in ( (S.Alias obColAls, qualCol)
-       , OBNNothing
-       )
+    alias = Just $ mkAggregateOrderByAlias annAggOrderBy
+
+mkAnnOrderByAlias
+  :: Iden -> FieldName -> SimilarArrayFields -> AnnOrderByElementG v -> S.Alias
+mkAnnOrderByAlias pfx parAls similarFields = \case
+  AOCColumn pgColumnInfo ->
+    let pgColumn = pgiColumn pgColumnInfo
+        obColAls = mkBaseTableColumnAlias pfx pgColumn
+    in S.Alias obColAls
   -- "pfx.or.relname"."pfx.ob.or.relname.rest" AS "pfx.ob.or.relname.rest"
-  AOCObj (RelInfo rn _ colMapping relTab _) relFltr rest ->
-    let relPfx  = mkObjRelTableAls pfx rn
+  AOCObjectRelation relInfo _ rest ->
+    let rn = riName relInfo
+        relPfx  = mkObjectRelationTableAlias pfx rn
         ordByFldName = mkOrderByFieldName rn
-        ((nesAls, nesCol), ordByNode) =
-          processAnnOrderByCol relPfx ordByFldName emptyArrRelCtx strfyNum rest
-        (objNodeM, arrNodeM) = case ordByNode of
-          OBNNothing           -> (Nothing, Nothing)
-          OBNObjNode name node -> (Just (name, node), Nothing)
-          OBNArrNode als node  -> (Nothing, Just (als, node))
-        qualCol = S.mkQIdenExp relPfx nesAls
-        relBaseNode =
-          BaseNode relPfx Nothing (S.FISimple relTab Nothing)
-          (toSQLBoolExp (S.QualTable relTab) relFltr)
-          Nothing Nothing Nothing
-          (HM.singleton nesAls nesCol)
-          (maybe HM.empty (uncurry HM.singleton) objNodeM)
-          (maybe HM.empty (uncurry HM.singleton) arrNodeM)
-          HM.empty
-        relNode = ObjNode colMapping relBaseNode
-    in ( (nesAls, qualCol)
-       , OBNObjNode rn relNode
-       )
-  AOCAgg (RelInfo rn _ colMapping relTab _ ) relFltr annAggOb ->
-    let ArrNodeInfo arrAls arrPfx _ =
-          mkArrNodeInfo pfx parAls arrRelCtx $ ANIAggOrdBy rn
-        fldName = mkAggObFld annAggOb
-        qOrdBy = S.mkQIdenExp arrPfx $ toIden fldName
-        tabFrom = FromTable relTab
-        tabPerm = TablePerm relFltr Nothing
-        (extr, arrFlds) = mkAggObExtrAndFlds annAggOb
-        selFld = TAFAgg arrFlds
-        bn = mkBaseNode False (Prefixes arrPfx pfx) fldName selFld tabFrom
-             tabPerm noTableArgs Nothing strfyNum
-        aggNode = ArrNode [extr] colMapping $ mergeBaseNodes bn $
-                  mkEmptyBaseNode arrPfx tabFrom
-        obAls = arrPfx <> Iden "." <> toIden fldName
-    in ( (S.Alias obAls, qOrdBy)
-       , OBNArrNode arrAls aggNode
-       )
-
-processDistinctOnCol
+        nesAls = mkAnnOrderByAlias relPfx ordByFldName mempty rest
+    in nesAls
+  AOCArrayAggregation relInfo _ aggOrderBy ->
+    let rn = riName relInfo
+        arrPfx = mkArrayRelationSourcePrefix pfx parAls similarFields $
+                 mkOrderByFieldName rn
+        obAls = arrPfx <> Iden "." <> toIden (mkAggregateOrderByAlias aggOrderBy)
+    in S.Alias obAls
+
+processDistinctOnColumns
   :: Iden
   -> NE.NonEmpty PGCol
   -> ( S.DistinctExpr
-     -- additional column extractors
-     , [(S.Alias, S.SQLExp)]
+     , [(S.Alias, S.SQLExp)] -- additional column extractors
      )
-processDistinctOnCol pfx neCols = (distOnExp, colExtrs)
+processDistinctOnColumns pfx neCols = (distOnExp, colExtrs)
   where
     cols = toList neCols
     distOnExp = S.DistinctOn $ map (S.SEIden . toIden . mkQColAls) cols
-    mkQCol c = S.mkQIdenExp (mkBaseTableAls pfx) $ toIden c
-    mkQColAls = S.Alias . mkBaseTableColAls pfx
+    mkQCol c = S.mkQIdenExp (mkBaseTableAlias pfx) $ toIden c
+    mkQColAls = S.Alias . mkBaseTableColumnAlias pfx
     colExtrs = flip map cols $ mkQColAls &&& mkQCol
 
+type SimilarArrayFields = HM.HashMap FieldName [FieldName]
 
-mkEmptyBaseNode :: Iden -> SelectFrom -> BaseNode
-mkEmptyBaseNode pfx selectFrom =
-  BaseNode pfx Nothing fromItem (S.BELit True) Nothing Nothing
-  Nothing selOne HM.empty HM.empty HM.empty
+mkSimilarArrayFields
+  :: Eq v
+  => AnnFieldsG v
+  -> Maybe (NE.NonEmpty (AnnOrderByItemG v))
+  -> SimilarArrayFields
+mkSimilarArrayFields annFields maybeOrderBys =
+  HM.fromList $ flip map allTuples $
+  \(relNameAndArgs, fieldName) -> (fieldName, getSimilarFields relNameAndArgs)
   where
-    selOne = HM.singleton (S.Alias $ pfx <> Iden "__one") (S.SEUnsafe "1")
-    fromItem = selFromToFromItem pfx selectFrom
-
-aggSelToArrNode :: Prefixes -> FieldName -> ArrRelAgg -> ArrNode
-aggSelToArrNode pfxs als aggSel =
-  ArrNode [extr] colMapping mergedBN
+    getSimilarFields relNameAndArgs = map snd $ filter ((== relNameAndArgs) . fst) allTuples
+    allTuples = arrayRelationTuples <> aggOrderByRelationTuples
+    arrayRelationTuples =
+      let arrayFields = mapMaybe getAnnArr annFields
+      in flip map arrayFields $
+         \(f, relSel) -> (getArrayRelNameAndSelectArgs relSel, f)
+
+    aggOrderByRelationTuples =
+      let mkItem (relName, fieldName) = ( (relName, noSelectArgs)
+                                        , fieldName
+                                        )
+      in map mkItem $ maybe []
+         (mapMaybe (fetchAggOrderByRels . obiColumn) . toList) maybeOrderBys
+
+    fetchAggOrderByRels (AOCArrayAggregation ri _ _) =
+      Just (riName ri, mkOrderByFieldName $ riName ri)
+    fetchAggOrderByRels _               = Nothing
+
+getArrayRelNameAndSelectArgs :: ArraySelectG v -> (RelName, SelectArgsG v)
+getArrayRelNameAndSelectArgs = \case
+  ASSimple r -> (aarRelationshipName r, _asnArgs $ aarAnnSelect r)
+  ASAggregate r -> (aarRelationshipName r, _asnArgs $ aarAnnSelect r)
+  ASConnection r -> (aarRelationshipName r, _asnArgs $ _csSelect $ aarAnnSelect r)
+
+getAnnArr :: (a, AnnFieldG v) -> Maybe (a, ArraySelectG v)
+getAnnArr (f, annFld) = case annFld of
+  AFArrayRelation ar -> Just (f, ar)
+  _                  -> Nothing
+
+
+withWriteJoinTree
+  :: (MonadWriter JoinTree m)
+  => (JoinTree -> b -> JoinTree)
+  -> m (a, b)
+  -> m a
+withWriteJoinTree joinTreeUpdater action =
+  pass $ do
+    (out, result) <- action
+    let fromJoinTree joinTree =
+          joinTreeUpdater joinTree result
+    pure (out, fromJoinTree)
+
+withWriteObjectRelation
+  :: (MonadWriter JoinTree m)
+  => m ( ObjectRelationSource
+       , HM.HashMap S.Alias S.SQLExp
+       , a
+       )
+  -> m a
+withWriteObjectRelation action =
+  withWriteJoinTree updateJoinTree $ do
+    (source, nodeExtractors, out) <- action
+    pure (out, (source, nodeExtractors))
   where
-    AnnRelG _ colMapping annSel = aggSel
-    AnnSelG aggFlds tabFrm tabPerm tabArgs strfyNum = annSel
-    fldAls = S.Alias $ toIden als
-
-    extr = flip S.Extractor (Just fldAls) $ S.applyJsonBuildObj $
-           concatMap selFldToExtr aggFlds
-
-    permLimit = _tpLimit tabPerm
-    ordBy = _bnOrderBy mergedBN
-
-    allBNs = map mkAggBaseNode aggFlds
-    emptyBN = mkEmptyBaseNode (_pfThis pfxs) tabFrm
-    mergedBN = foldr mergeBaseNodes emptyBN allBNs
-
-    mkAggBaseNode (fn, selFld) =
-      mkBaseNode subQueryReq pfxs fn selFld tabFrm tabPerm tabArgs Nothing strfyNum
-
-    selFldToExtr (FieldName t, fld) = (:) (S.SELit t) $ pure $ case fld of
-      TAFAgg flds -> aggFldToExp flds
-      TAFNodes _  ->
-        withJsonAggExtr subQueryReq permLimit ordBy $ S.Alias $ Iden t
-      TAFExp e    ->
-        -- bool_or to force aggregation
-        S.SEFnApp "coalesce"
-        [ S.SELit e , S.SEUnsafe "bool_or('true')::text"] Nothing
-
-    subQueryReq = hasAggFld aggFlds
-
-hasAggFld :: Foldable t => t (a, TableAggFldG v) -> Bool
-hasAggFld = any (isTabAggFld . snd)
+    updateJoinTree joinTree (source, nodeExtractors) =
+      let selectNode = SelectNode nodeExtractors joinTree
+      in mempty{_jtObjectRelations = HM.singleton source selectNode}
+
+withWriteArrayRelation
+  :: (MonadWriter JoinTree m)
+  => m ( ArrayRelationSource
+       , S.Extractor
+       , HM.HashMap S.Alias S.SQLExp
+       , a
+       )
+  -> m a
+withWriteArrayRelation action =
+  withWriteJoinTree updateJoinTree $ do
+  (source, topExtractor, nodeExtractors, out) <- action
+  pure (out, (source, topExtractor, nodeExtractors))
   where
-    isTabAggFld (TAFAgg _) = True
-    isTabAggFld _          = False
-
-mkArrNodeInfo
-  :: Iden
-  -> FieldName
-  -> ArrRelCtx
-  -> ArrNodeItem
-  -> ArrNodeInfo
-mkArrNodeInfo pfx parAls (ArrRelCtx arrFlds obRels) = \case
-  ANIField aggFld@(fld, annArrSel) ->
-    let (rn, tabArgs) = fetchRNAndTArgs annArrSel
-        similarFlds = getSimilarAggFlds rn tabArgs $ delete aggFld
-        similarFldNames = map fst similarFlds
-        similarOrdByFound = rn `elem` obRels && tabArgs == noTableArgs
-        ordByFldName = mkOrderByFieldName rn
-        extraOrdByFlds = bool [] [ordByFldName] similarOrdByFound
-        sortedFlds = sort $ fld : (similarFldNames <> extraOrdByFlds)
-        alias = S.Alias $ mkUniqArrRelAls parAls sortedFlds
-        prefix = mkArrRelTableAls pfx parAls sortedFlds
-    in ArrNodeInfo alias prefix $
-       subQueryRequired similarFlds similarOrdByFound
-  ANIAggOrdBy rn ->
-    let similarFlds = map fst $ getSimilarAggFlds rn noTableArgs id
-        ordByFldName = mkOrderByFieldName rn
-        sortedFlds = sort $ ordByFldName:similarFlds
-        alias = S.Alias $ mkUniqArrRelAls parAls sortedFlds
-        prefix = mkArrRelTableAls pfx parAls sortedFlds
-    in ArrNodeInfo alias prefix False
+    updateJoinTree joinTree (source, topExtractor, nodeExtractors) =
+      let arraySelectNode = ArraySelectNode [topExtractor] $
+                            SelectNode nodeExtractors joinTree
+      in mempty{_jtArrayRelations = HM.singleton source arraySelectNode}
+
+withWriteArrayConnection
+  :: (MonadWriter JoinTree m)
+  => m ( ArrayConnectionSource
+       , S.Extractor
+       , HM.HashMap S.Alias S.SQLExp
+       , a
+       )
+  -> m a
+withWriteArrayConnection action =
+  withWriteJoinTree updateJoinTree $ do
+  (source, topExtractor, nodeExtractors, out) <- action
+  pure (out, (source, topExtractor, nodeExtractors))
   where
-    getSimilarAggFlds rn tabArgs f =
-      flip filter (f arrFlds) $ \(_, annArrSel) ->
-        let (lrn, lTabArgs) = fetchRNAndTArgs annArrSel
-        in (lrn == rn) && (lTabArgs == tabArgs)
-
-    subQueryRequired similarFlds hasSimOrdBy =
-      hasSimOrdBy || any hasAgg similarFlds
-
-    hasAgg (_, ASSimple _)                 = False
-    hasAgg (_, ASAgg (AnnRelG _ _ annSel)) = hasAggFld $ _asnFields annSel
-
-    fetchRNAndTArgs (ASSimple (AnnRelG rn _ annSel)) =
-      (rn, _asnArgs annSel)
-    fetchRNAndTArgs (ASAgg (AnnRelG rn _ annSel)) =
-      (rn, _asnArgs annSel)
-
-fetchOrdByAggRels
-  :: Maybe (NE.NonEmpty AnnOrderByItem)
-  -> [RelName]
-fetchOrdByAggRels orderByM = fromMaybe [] relNamesM
+    updateJoinTree joinTree (source, topExtractor, nodeExtractors) =
+      let arraySelectNode = ArraySelectNode [topExtractor] $
+                            SelectNode nodeExtractors joinTree
+      in mempty{_jtArrayConnections = HM.singleton source arraySelectNode}
+
+withWriteComputedFieldTableSet
+  :: (MonadWriter JoinTree m)
+  => m ( ComputedFieldTableSetSource
+       , HM.HashMap S.Alias S.SQLExp
+       , a
+       )
+  -> m a
+withWriteComputedFieldTableSet action =
+  withWriteJoinTree updateJoinTree $ do
+    (source, nodeExtractors, out) <- action
+    pure (out, (source, nodeExtractors))
   where
-    relNamesM =
-      mapMaybe (fetchAggOrdByRels . obiColumn) . toList <$> orderByM
+    updateJoinTree joinTree (source, nodeExtractors) =
+      let selectNode = SelectNode nodeExtractors joinTree
+      in mempty{_jtComputedFieldTableSets = HM.singleton source selectNode}
 
-    fetchAggOrdByRels (AOCAgg ri _ _) = Just $ riName ri
-    fetchAggOrdByRels _               = Nothing
 
-mkOrdByItems
-  :: Iden -> FieldName
-  -> Maybe (NE.NonEmpty AnnOrderByItem)
-  -> Bool
-  -> ArrRelCtx
-     -- extractors
-  -> ( [(S.Alias, S.SQLExp)]
-     -- object relation nodes
-     , HM.HashMap RelName ObjNode
-     -- array relation aggregate nodes
-     , HM.HashMap S.Alias ArrNode
-     -- final order by expression
-     , Maybe S.OrderByExp
-     )
-mkOrdByItems pfx fldAls orderByM strfyNum arrRelCtx =
-  (obExtrs, ordByObjsMap, ordByArrsMap, ordByExpM)
+processAnnSimpleSelect
+  :: forall m. ( MonadReader Bool m
+               , MonadWriter JoinTree m
+               )
+  => SourcePrefixes
+  -> FieldName
+  -> PermissionLimitSubQuery
+  -> AnnSimpleSel
+  -> m ( SelectSource
+       , HM.HashMap S.Alias S.SQLExp
+       )
+processAnnSimpleSelect sourcePrefixes fieldAlias permLimitSubQuery annSimpleSel = do
+  (selectSource, orderByAndDistinctExtrs, _) <-
+    processSelectParams sourcePrefixes fieldAlias similarArrayFields tableFrom
+    permLimitSubQuery tablePermissions tableArgs
+  annFieldsExtr <- processAnnFields (_pfThis sourcePrefixes) fieldAlias similarArrayFields annSelFields
+  let allExtractors = HM.fromList $ annFieldsExtr : orderByAndDistinctExtrs
+  pure (selectSource, allExtractors)
   where
-    procAnnOrdBy' = processAnnOrderByItem pfx fldAls arrRelCtx strfyNum
-    procOrdByM =
-      unzip3 . map procAnnOrdBy' . toList <$> orderByM
-
-    obExtrs  = maybe [] (^. _1) procOrdByM
-    ordByExpM  = S.OrderByExp . (^. _2) <$> procOrdByM
-
-    ordByObjs = mapMaybe getOrdByRelNode $ maybe [] (^. _3) procOrdByM
-    ordByObjsMap = HM.fromListWith mergeObjNodes ordByObjs
-
-    ordByAggArrs = mapMaybe getOrdByAggNode $ maybe [] (^. _3) procOrdByM
-    ordByArrsMap = HM.fromListWith mergeArrNodes ordByAggArrs
-
-    getOrdByRelNode (OBNObjNode name node) = Just (name, node)
-    getOrdByRelNode _                      = Nothing
-
-    getOrdByAggNode (OBNArrNode als node) = Just (als, node)
-    getOrdByAggNode _                     = Nothing
-
-cursorAlias :: S.Alias
-cursorAlias = S.Alias $ Iden "__cursor"
+    AnnSelectG annSelFields tableFrom tablePermissions tableArgs _ = annSimpleSel
+    similarArrayFields =
+      mkSimilarArrayFields annSelFields $ _saOrderBy tableArgs
+
+processAnnAggregateSelect
+  :: forall m. ( MonadReader Bool m
+               , MonadWriter JoinTree m
+               )
+  => SourcePrefixes
+  -> FieldName
+  -> AnnAggregateSelect
+  -> m ( SelectSource
+       , HM.HashMap S.Alias S.SQLExp
+       , S.Extractor
+       )
+processAnnAggregateSelect sourcePrefixes fieldAlias annAggSel = do
+  (selectSource, orderByAndDistinctExtrs, _) <-
+    processSelectParams sourcePrefixes fieldAlias similarArrayFields tableFrom
+    permLimitSubQuery tablePermissions tableArgs
+  let thisSourcePrefix = _pfThis sourcePrefixes
+  processedFields <- forM aggSelFields $ \(fieldName, field) ->
+    (fieldName,) <$>
+    case field of
+      TAFAgg aggFields ->
+        pure ( aggregateFieldsToExtractorExps thisSourcePrefix aggFields
+             , aggregateFieldToExp aggFields
+             )
+      TAFNodes annFields -> do
+        annFieldExtr <- processAnnFields thisSourcePrefix fieldName similarArrayFields annFields
+        pure ( [annFieldExtr]
+             , withJsonAggExtr permLimitSubQuery (_ssOrderBy selectSource) $
+               S.Alias $ toIden fieldName
+             )
+      TAFExp e ->
+        pure ( []
+             -- bool_or to force aggregation
+             , S.SEFnApp "coalesce"
+               [ S.SELit e , S.SEUnsafe "bool_or('true')::text"] Nothing
+             )
 
-mkCursorExtractor :: Iden -> [PGCol] -> S.SQLExp
-mkCursorExtractor pfx columns =
-  flip S.SETyAnn S.textTypeAnn $
-  S.applyJsonBuildObj $ flip concatMap columns $
-  \column -> [ S.SELit $ getPGColTxt column
-             , S.mkQIdenExp (mkBaseTableAls pfx) column
-             ]
+  let topLevelExtractor =
+        flip S.Extractor (Just $ S.Alias $ toIden fieldAlias) $
+        S.applyJsonBuildObj $ flip concatMap (map (second snd) processedFields) $
+        \(FieldName fieldText, fieldExp) -> [S.SELit fieldText, fieldExp]
+      nodeExtractors = HM.fromList $
+        concatMap (fst . snd) processedFields <> orderByAndDistinctExtrs
 
-mkBaseNode
-  :: Bool
-  -> Prefixes
+  pure (selectSource, nodeExtractors, topLevelExtractor)
+  where
+    AnnSelectG aggSelFields tableFrom tablePermissions tableArgs _ = annAggSel
+    permLimit = _tpLimit tablePermissions
+    orderBy = _saOrderBy tableArgs
+    permLimitSubQuery = mkPermissionLimitSubQuery permLimit aggSelFields orderBy
+    similarArrayFields = HM.unions $
+      flip map (map snd aggSelFields) $ \case
+        TAFAgg _ -> mempty
+        TAFNodes annFlds ->
+          mkSimilarArrayFields annFlds orderBy
+        TAFExp _ -> mempty
+
+mkPermissionLimitSubQuery
+  :: Maybe Int
+  -> TableAggregateFields
+  -> Maybe (NE.NonEmpty AnnOrderByItem)
+  -> PermissionLimitSubQuery
+mkPermissionLimitSubQuery permLimit aggFields orderBys =
+  case permLimit of
+    Nothing -> PLSQNotRequired
+    Just limit ->
+      if hasAggregateField || hasAggOrderBy then PLSQRequired limit
+      else PLSQNotRequired
+  where
+    hasAggregateField = flip any (map snd aggFields) $
+      \case
+        TAFAgg _ -> True
+        _        -> False
+
+    hasAggOrderBy = case orderBys of
+      Nothing -> False
+      Just l -> flip any (concatMap toList $ toList l) $
+                \case
+                  AOCArrayAggregation{} -> True
+                  _        -> False
+
+processArrayRelation
+  :: forall m. ( MonadReader Bool m
+               , MonadWriter JoinTree m
+               )
+  => SourcePrefixes
   -> FieldName
-  -> TableAggFld
+  -> S.Alias
+  -> ArraySelect
+  -> m ()
+processArrayRelation sourcePrefixes fieldAlias relAlias arrSel =
+  case arrSel of
+    ASSimple annArrRel -> withWriteArrayRelation $ do
+      let AnnRelationSelectG _ colMapping sel = annArrRel
+          permLimitSubQuery =
+            maybe PLSQNotRequired PLSQRequired $ _tpLimit $ _asnPerm sel
+      (source, nodeExtractors) <-
+        processAnnSimpleSelect sourcePrefixes fieldAlias permLimitSubQuery sel
+      let topExtr = asJsonAggExtr JASMultipleRows (S.toAlias fieldAlias)
+                    permLimitSubQuery $ _ssOrderBy source
+      pure ( ArrayRelationSource relAlias colMapping source
+           , topExtr
+           , nodeExtractors
+           , ()
+           )
+    ASAggregate aggSel -> withWriteArrayRelation $ do
+      let AnnRelationSelectG _ colMapping sel = aggSel
+      (source, nodeExtractors, topExtr) <-
+        processAnnAggregateSelect sourcePrefixes fieldAlias sel
+      pure ( ArrayRelationSource relAlias colMapping source
+           , topExtr
+           , nodeExtractors
+           , ()
+           )
+    ASConnection connSel -> withWriteArrayConnection $ do
+      let AnnRelationSelectG _ colMapping sel = connSel
+      (source, topExtractor, nodeExtractors) <-
+        processConnectionSelect sourcePrefixes fieldAlias relAlias colMapping sel
+      pure ( source
+           , topExtractor
+           , nodeExtractors
+           , ()
+           )
+
+processSelectParams
+  :: forall m. ( MonadReader Bool m
+               , MonadWriter JoinTree m
+               )
+  => SourcePrefixes
+  -> FieldName
+  -> SimilarArrayFields
   -> SelectFrom
+  -> PermissionLimitSubQuery
   -> TablePerm
-  -> TableArgs
-  -> Maybe (NonEmpty PGCol)
-  -> Bool
-  -> BaseNode
-mkBaseNode subQueryReq pfxs fldAls annSelFlds selectFrom
-           tablePerm tableArgs primaryKeyColumns strfyNum =
-
-  BaseNode thisPfx distExprM fromItem finalWhere ordByExpM finalLimit offsetM
-  allExtrs allObjsWithOb allArrsWithOb computedFields
+  -> SelectArgs
+  -> m ( SelectSource
+       , [(S.Alias, S.SQLExp)]
+       , Maybe S.SQLExp -- Order by cursor
+       )
+processSelectParams sourcePrefixes fieldAlias similarArrFields selectFrom
+                    permLimitSubQ tablePermissions tableArgs = do
+  maybeOrderBy <- mapM
+                  (processOrderByItems thisSourcePrefix fieldAlias similarArrFields)
+                  orderByM
+  let fromItem = selectFromToFromItem (_pfBase sourcePrefixes) selectFrom
+      (maybeDistinct, distinctExtrs) =
+        maybe (Nothing, []) (first Just) $ processDistinctOnColumns thisSourcePrefix <$> distM
+      finalWhere = toSQLBoolExp (selectFromToQual selectFrom) $
+                   maybe permFilter (andAnnBoolExps permFilter) whereM
+      selectSource = SelectSource thisSourcePrefix fromItem maybeDistinct finalWhere
+                     ((^. _2) <$> maybeOrderBy) finalLimit offsetM
+      orderByExtrs = maybe [] (^. _1) maybeOrderBy
+  pure ( selectSource
+       , orderByExtrs <> distinctExtrs
+       , (^. _3) <$> maybeOrderBy
+       )
   where
-    Prefixes thisPfx baseTablepfx = pfxs
-    TablePerm permFilter permLimit = tablePerm
-    TableArgs whereM orderByM inpLimitM offsetM distM = tableArgs
-
-    -- if sub query is used, then only use input limit
+    thisSourcePrefix = _pfThis sourcePrefixes
+    SelectArgs whereM orderByM inpLimitM offsetM distM = tableArgs
+    TablePerm permFilter permLimit = tablePermissions
+    finalLimit =
+    -- if sub query is required, then only use input limit
     --    because permission limit is being applied in subquery
     -- else compare input and permission limits
-    finalLimit =
-      if subQueryReq then inpLimitM
-      else withPermLimit
+      case permLimitSubQ of
+        PLSQRequired _  -> inpLimitM
+        PLSQNotRequired -> compareLimits
 
-    withPermLimit =
+    compareLimits =
       case (inpLimitM, permLimit) of
         (inpLim, Nothing)     -> inpLim
         (Nothing, permLim)    -> permLim
         (Just inp, Just perm) -> Just $ if inp < perm then inp else perm
 
-
-    aggOrdByRelNames = fetchOrdByAggRels orderByM
-
-    (allExtrs, allObjsWithOb, allArrsWithOb, computedFields, ordByExpM) =
-      case annSelFlds of
-        TAFNodes flds ->
-          let arrFlds = mapMaybe getAnnArr flds
-              arrRelCtx = mkArrRelCtx arrFlds
-              selExtr = buildJsonObject thisPfx fldAls arrRelCtx strfyNum flds
-              cursorExtrs = maybe [] (pure . (cursorAlias,) . mkCursorExtractor thisPfx . toList)
-                            primaryKeyColumns
-              -- all object relationships
-              objNodes = HM.fromListWith mergeObjNodes $
-                        map mkObjItem (mapMaybe getAnnObj flds)
-              -- all array items (array relationships + aggregates)
-              arrNodes = HM.fromListWith mergeArrNodes $
-                         map (mkArrItem arrRelCtx) arrFlds
-              -- all computed fields with table returns
-              computedFieldNodes = HM.fromList $ map mkComputedFieldTable $
-                                   mapMaybe getComputedFieldTable flds
-
-              (obExtrs, ordByObjs, ordByArrs, obeM)
-                      = mkOrdByItems' arrRelCtx
-              allObjs = HM.unionWith mergeObjNodes objNodes ordByObjs
-              allArrs = HM.unionWith mergeArrNodes arrNodes ordByArrs
-
-          in ( HM.fromList $ selExtr:obExtrs <> distExtrs <> cursorExtrs
-             , allObjs
-             , allArrs
-             , computedFieldNodes
-             , obeM
-             )
-        TAFAgg tabAggs ->
-          let extrs = concatMap (fetchExtrFromAggFld . snd) tabAggs
-              (obExtrs, ordByObjs, ordByArrs, obeM)
-                      = mkOrdByItems' emptyArrRelCtx
-          in ( HM.fromList $ extrs <> obExtrs <> distExtrs
-             , ordByObjs
-             , ordByArrs
-             , HM.empty
-             , obeM
-             )
-        TAFExp _ ->
-          let (obExtrs, ordByObjs, ordByArrs, obeM)
-                      = mkOrdByItems' emptyArrRelCtx
-          in (HM.fromList obExtrs, ordByObjs, ordByArrs, HM.empty, obeM)
-
-    fetchExtrFromAggFld (AFCount cty) = countTyToExps cty
-    fetchExtrFromAggFld (AFOp aggOp)  = aggOpToExps aggOp
-    fetchExtrFromAggFld (AFExp _)     = []
-
-    countTyToExps S.CTStar            = []
-    countTyToExps (S.CTSimple cols)   = colsToExps cols
-    countTyToExps (S.CTDistinct cols) = colsToExps cols
-
+processOrderByItems
+  :: forall m. ( MonadReader Bool m
+               , MonadWriter JoinTree m
+               )
+  => Iden
+  -> FieldName
+  -> SimilarArrayFields
+  -> NE.NonEmpty AnnOrderByItem
+  -> m ( [(S.Alias, S.SQLExp)] -- Order by Extractors
+       , S.OrderByExp
+       , S.SQLExp -- The cursor expression
+       )
+processOrderByItems sourcePrefix' fieldAlias' similarArrayFields orderByItems = do
+  orderByItemExps <- forM orderByItems processAnnOrderByItem
+  let orderByExp = S.OrderByExp $ toOrderByExp <$> orderByItemExps
+      orderByExtractors = concat $ toList $ map snd . toList <$> orderByItemExps
+      cursor = mkCursorExp $ toList orderByItemExps
+  pure (orderByExtractors, orderByExp, cursor)
+  where
+    processAnnOrderByItem :: AnnOrderByItem -> m OrderByItemExp
+    processAnnOrderByItem orderByItem =
+      forM orderByItem $ \ordByCol -> (ordByCol,) <$>
+      processAnnOrderByElement sourcePrefix' fieldAlias' ordByCol
+
+    processAnnOrderByElement
+      :: Iden -> FieldName -> AnnOrderByElement S.SQLExp -> m (S.Alias, S.SQLExp)
+    processAnnOrderByElement sourcePrefix fieldAlias annObCol = do
+      let ordByAlias = mkAnnOrderByAlias sourcePrefix fieldAlias similarArrayFields annObCol
+      (ordByAlias, ) <$> case annObCol of
+        AOCColumn pgColInfo -> pure $
+          S.mkQIdenExp (mkBaseTableAlias sourcePrefix) $ toIden $ pgiColumn pgColInfo
+
+        AOCObjectRelation relInfo relFilter rest -> withWriteObjectRelation $ do
+          let RelInfo relName _ colMapping relTable _ = relInfo
+              relSourcePrefix = mkObjectRelationTableAlias sourcePrefix relName
+              fieldName = mkOrderByFieldName relName
+          (relOrderByAlias, relOrdByExp) <-
+            processAnnOrderByElement relSourcePrefix fieldName rest
+          let selectSource = SelectSource relSourcePrefix
+                             (S.FISimple relTable Nothing) Nothing
+                             (toSQLBoolExp (S.QualTable relTable) relFilter)
+                             Nothing Nothing Nothing
+              relSource = ObjectRelationSource relName colMapping selectSource
+          pure ( relSource
+               , HM.singleton relOrderByAlias relOrdByExp
+               , S.mkQIdenExp relSourcePrefix relOrderByAlias
+               )
+
+        AOCArrayAggregation relInfo relFilter aggOrderBy -> withWriteArrayRelation $ do
+          let RelInfo relName _ colMapping relTable _ = relInfo
+              fieldName = mkOrderByFieldName relName
+              relSourcePrefix = mkArrayRelationSourcePrefix sourcePrefix fieldAlias
+                                similarArrayFields fieldName
+              relAlias = mkArrayRelationAlias fieldAlias similarArrayFields fieldName
+              (topExtractor, fields) = mkAggregateOrderByExtractorAndFields aggOrderBy
+              selectSource = SelectSource relSourcePrefix
+                             (S.FISimple relTable Nothing) Nothing
+                             (toSQLBoolExp (S.QualTable relTable) relFilter)
+                             Nothing Nothing Nothing
+              relSource = ArrayRelationSource relAlias colMapping selectSource
+          pure ( relSource
+               , topExtractor
+               , HM.fromList $ aggregateFieldsToExtractorExps relSourcePrefix fields
+               , S.mkQIdenExp relSourcePrefix (mkAggregateOrderByAlias aggOrderBy)
+               )
+
+    toOrderByExp :: OrderByItemExp -> S.OrderByItem
+    toOrderByExp orderByItemExp =
+      let OrderByItemG obTyM expAlias obNullsM = fst . snd <$> orderByItemExp
+      in S.OrderByItem (S.SEIden $ toIden expAlias)
+         (unOrderType <$> obTyM) (unNullsOrder <$> obNullsM)
+
+    mkCursorExp :: [OrderByItemExp] -> S.SQLExp
+    mkCursorExp orderByItemExps =
+      S.applyJsonBuildObj $ flip concatMap orderByItemExps $
+      \orderByItemExp ->
+        let OrderByItemG _ (annObCol, (_, valExp)) _ = orderByItemExp
+        in annObColToJSONField valExp annObCol
+      where
+        annObColToJSONField valExp = \case
+          AOCColumn pgCol -> [S.SELit $ getPGColTxt $ pgiColumn pgCol, valExp]
+          AOCObjectRelation relInfo _ obCol ->
+            [ S.SELit $ relNameToTxt $ riName relInfo
+            , S.applyJsonBuildObj $ annObColToJSONField valExp obCol
+            ]
+          AOCArrayAggregation relInfo _ aggOrderBy ->
+            [ S.SELit $ relNameToTxt (riName relInfo) <> "_aggregate"
+            , S.applyJsonBuildObj $
+              case aggOrderBy of
+                AAOCount -> [S.SELit "count", valExp]
+                AAOOp opText colInfo ->
+                  [ S.SELit opText
+                  , S.applyJsonBuildObj [S.SELit $ getPGColTxt $ pgiColumn colInfo, valExp]
+                  ]
+            ]
+
+aggregateFieldsToExtractorExps
+  :: Iden -> AggregateFields -> [(S.Alias, S.SQLExp)]
+aggregateFieldsToExtractorExps sourcePrefix aggregateFields =
+  flip concatMap aggregateFields $ \(_, field) ->
+    case field of
+      AFCount cty -> case cty of
+        S.CTStar          -> []
+        S.CTSimple cols   -> colsToExps cols
+        S.CTDistinct cols -> colsToExps cols
+      AFOp aggOp  -> aggOpToExps aggOp
+      AFExp _     -> []
+  where
     colsToExps = mapMaybe (mkColExp . PCFCol)
-
-    aggOpToExps = mapMaybe (mkColExp . snd) . _aoFlds
+    aggOpToExps = mapMaybe (mkColExp . snd) . _aoFields
 
     mkColExp (PCFCol c) =
-      let qualCol = S.mkQIdenExp (mkBaseTableAls thisPfx) (toIden c)
+      let qualCol = S.mkQIdenExp (mkBaseTableAlias sourcePrefix) (toIden c)
           colAls = toIden c
       in Just (S.Alias colAls, qualCol)
     mkColExp _ = Nothing
 
-    finalWhere = toSQLBoolExp tableQual $
-                 maybe permFilter (andAnnBoolExps permFilter) whereM
-    fromItem = selFromToFromItem baseTablepfx selectFrom
-    tableQual = selFromToQual selectFrom
-
-    mkArrRelCtx arrSels = ArrRelCtx arrSels aggOrdByRelNames
-
-    mkOrdByItems' = mkOrdByItems thisPfx fldAls orderByM strfyNum
-
-    distItemsM = processDistinctOnCol thisPfx <$> distM
-    distExprM = fst <$> distItemsM
-    distExtrs = maybe [] snd distItemsM
-
-    -- process an object relationship
-    mkObjItem (fld, objSel) =
-      let relName = aarName objSel
-          objNodePfx = mkObjRelTableAls thisPfx $ aarName objSel
-          objNode = mkObjNode (Prefixes objNodePfx thisPfx) (fld, objSel)
-      in (relName, objNode)
-
-    -- process an array/array-aggregate item
-    mkArrItem arrRelCtx (fld, arrSel) =
-      let ArrNodeInfo arrAls arrPfx subQReq =
-            mkArrNodeInfo thisPfx fldAls arrRelCtx $ ANIField (fld, arrSel)
-          arrNode = mkArrNode subQReq (Prefixes arrPfx thisPfx) (fld, arrSel)
-      in (arrAls, arrNode)
-
-    -- process a computed field, which returns a table
-    mkComputedFieldTable (fld, jsonAggSelect, sel) =
-      let prefixes = Prefixes (mkComputedFieldTableAls thisPfx fld) thisPfx
-          baseNode = annSelToBaseNode False prefixes fld Nothing sel
-      in (fld, CFTableNode jsonAggSelect baseNode)
-
-    getAnnObj (f, annFld) = case annFld of
-      FObj ob -> Just (f, ob)
-      _       -> Nothing
-
-    getAnnArr (f, annFld) = case annFld of
-      FArr ar -> Just (f, ar)
-      _       -> Nothing
-
-    getComputedFieldTable (f, annFld) = case annFld of
-      FComputedField (CFSTable jas sel) -> Just (f, jas, sel)
-      _                                 -> Nothing
-
-annSelToBaseNode
-  :: Bool -> Prefixes -> FieldName -> Maybe (NonEmpty PGCol) -> AnnSimpleSel -> BaseNode
-annSelToBaseNode subQueryReq pfxs fldAls pkeyCols annSel =
-  mkBaseNode subQueryReq pfxs fldAls (TAFNodes selFlds) tabFrm tabPerm tabArgs pkeyCols strfyNum
-  where
-    AnnSelG selFlds tabFrm tabPerm tabArgs strfyNum = annSel
+processAnnFields
+  :: forall m. ( MonadReader Bool m
+               , MonadWriter JoinTree m
+               )
+  => Iden
+  -> FieldName
+  -> SimilarArrayFields
+  -> AnnFields
+  -> m (S.Alias, S.SQLExp)
+processAnnFields sourcePrefix fieldAlias similarArrFields annFields = do
+  fieldExps <- forM annFields $ \(fieldName, field) ->
+    (fieldName,) <$>
+    case field of
+      AFExpression t -> pure $ S.SELit t
+
+      AFColumn c -> toSQLCol c
+
+      AFObjectRelation objSel -> withWriteObjectRelation $ do
+        let AnnRelationSelectG relName relMapping annSel = objSel
+            objRelSourcePrefix = mkObjectRelationTableAlias sourcePrefix relName
+        (selectSource, extractors) <- processAnnSimpleSelect (mkSourcePrefixes objRelSourcePrefix)
+                                        fieldName PLSQNotRequired annSel
+        let objRelSource = ObjectRelationSource relName relMapping selectSource
+        pure ( objRelSource
+             , extractors
+             , S.mkQIdenExp objRelSourcePrefix fieldName
+             )
 
-mkObjNode :: Prefixes -> (FieldName, ObjSel) -> ObjNode
-mkObjNode pfxs (fldName, AnnRelG _ rMapn rAnnSel) =
-  ObjNode rMapn $ annSelToBaseNode False pfxs fldName Nothing rAnnSel
+      AFArrayRelation arrSel -> do
+        let arrRelSourcePrefix = mkArrayRelationSourcePrefix sourcePrefix fieldAlias similarArrFields fieldName
+            arrRelAlias = mkArrayRelationAlias fieldAlias similarArrFields fieldName
+        processArrayRelation (mkSourcePrefixes arrRelSourcePrefix) fieldName arrRelAlias arrSel
+        pure $ S.mkQIdenExp arrRelSourcePrefix fieldName
+
+      AFComputedField (CFSScalar scalar) -> fromScalarComputedField scalar
+
+      AFComputedField (CFSTable selectTy sel) -> withWriteComputedFieldTableSet $ do
+        let computedFieldSourcePrefix =
+              mkComputedFieldTableAlias sourcePrefix fieldName
+        (selectSource, nodeExtractors) <-
+          processAnnSimpleSelect (mkSourcePrefixes computedFieldSourcePrefix)
+          fieldName PLSQNotRequired sel
+        let computedFieldTableSetSource =
+              ComputedFieldTableSetSource fieldName selectTy selectSource
+        pure ( computedFieldTableSetSource
+             , nodeExtractors
+             , S.mkQIdenExp computedFieldSourcePrefix fieldName
+             )
 
-mkArrNode :: Bool -> Prefixes -> (FieldName, ArrSel) -> ArrNode
-mkArrNode subQueryReq pfxs (fldName, annArrSel) = case annArrSel of
-  ASSimple annArrRel ->
-    let bn = annSelToBaseNode subQueryReq pfxs fldName Nothing $ aarAnnSel annArrRel
-        permLimit = getPermLimit $ aarAnnSel annArrRel
-        extr = asJsonAggExtr JASMultipleRows (S.toAlias fldName) subQueryReq permLimit $
-               _bnOrderBy bn
-    in ArrNode [extr] (aarMapping annArrRel) bn
+  pure $
+    -- posttgres ignores anything beyond 63 chars for an iden
+    -- in this case, we'll need to use json_build_object function
+    -- json_build_object is slower than row_to_json hence it is only
+    -- used when needed
+    if any ( (> 63) . T.length . getFieldNameTxt . fst ) fieldExps then
+      withJsonBuildObj fieldAlias $ concatMap toJsonBuildObjectExps fieldExps
+    else withRowToJSON fieldAlias $ map toRowToJsonExtr fieldExps
+  where
+    mkSourcePrefixes newPrefix = SourcePrefixes newPrefix sourcePrefix
+    toJsonBuildObjectExps (fieldName, fieldExp) =
+      [S.SELit $ getFieldNameTxt fieldName, fieldExp]
+
+    toRowToJsonExtr (fieldName, fieldExp) =
+      S.Extractor fieldExp $ Just $ S.toAlias fieldName
+
+    toSQLCol :: AnnColumnField -> m S.SQLExp
+    toSQLCol (AnnColumnField col asText colOpM) = do
+      strfyNum <- ask
+      pure $ toJSONableExp strfyNum (pgiType col) asText $ withColumnOp colOpM $
+             S.mkQIdenExp (mkBaseTableAlias sourcePrefix) $ pgiColumn col
+
+    fromScalarComputedField :: ComputedFieldScalarSelect S.SQLExp -> m S.SQLExp
+    fromScalarComputedField computedFieldScalar = do
+      strfyNum <- ask
+      pure $ toJSONableExp strfyNum (PGColumnScalar ty) False $ withColumnOp colOpM $
+             S.SEFunction $ S.FunctionExp fn (fromTableRowArgs sourcePrefix args) Nothing
+      where
+        ComputedFieldScalarSelect fn args ty colOpM = computedFieldScalar
 
-  ASAgg annAggSel -> aggSelToArrNode pfxs fldName annAggSel
-  ASConnection connectionSel -> connectionSelToArrNode pfxs fldName connectionSel
+    withColumnOp :: Maybe ColumnOp -> S.SQLExp -> S.SQLExp
+    withColumnOp colOpM sqlExp = case colOpM of
+      Nothing                     -> sqlExp
+      Just (ColumnOp opText cExp) -> S.mkSQLOpExp opText sqlExp cExp
 
 injectJoinCond :: S.BoolExp       -- ^ Join condition
                -> S.BoolExp -- ^ Where condition
@@ -715,28 +807,33 @@ mkJoinCond baseTablepfx colMapn =
   foldl' (S.BEBin S.AndOp) (S.BELit True) $ flip map (HM.toList colMapn) $ \(lCol, rCol) ->
     S.BECompare S.SEQ (S.mkQIdenExp baseTablepfx lCol) (S.mkSIdenExp rCol)
 
-baseNodeToSel :: S.BoolExp -> BaseNode -> S.Select
-baseNodeToSel joinCond baseNode =
+generateSQLSelect
+  :: S.BoolExp -- ^ Pre join condition
+  -> SelectSource
+  -> SelectNode
+  -> S.Select
+generateSQLSelect joinCondition selectSource selectNode =
   S.mkSelect
-  { S.selExtr    = [S.Extractor e $ Just a | (a, e) <- HM.toList extrs]
-  , S.selFrom    = Just $ S.FromExp [joinedFrom]
-  , S.selOrderBy = ordByM
-  , S.selLimit   = S.LimitExp . S.intToSQLExp <$> limitM
-  , S.selOffset  = S.OffsetExp <$> offsetM
-  , S.selDistinct = dExp
+  { S.selExtr = [S.Extractor e $ Just a | (a, e) <- HM.toList extractors]
+  , S.selFrom = Just $ S.FromExp [joinedFrom]
+  , S.selOrderBy = maybeOrderby
+  , S.selLimit = S.LimitExp . S.intToSQLExp <$> maybeLimit
+  , S.selOffset = S.OffsetExp <$> maybeOffset
+  , S.selDistinct = maybeDistinct
   }
   where
-    BaseNode pfx dExp fromItem whr ordByM limitM
-             offsetM extrs objRels arrRels computedFields
-             = baseNode
-    -- this is the table which is aliased as "pfx.base"
-    baseSel = S.mkSelect
+    SelectSource sourcePrefix fromItem maybeDistinct whereExp
+      maybeOrderby maybeLimit maybeOffset = selectSource
+    SelectNode extractors joinTree = selectNode
+    JoinTree objectRelations arrayRelations arrayConnections computedFields = joinTree
+    -- this is the table which is aliased as "sourcePrefix.base"
+    baseSelect = S.mkSelect
       { S.selExtr  = [S.Extractor (S.SEStar Nothing) Nothing]
       , S.selFrom  = Just $ S.FromExp [fromItem]
-      , S.selWhere = Just $ injectJoinCond joinCond whr
+      , S.selWhere = Just $ injectJoinCond joinCondition whereExp
       }
-    baseSelAls = S.Alias $ mkBaseTableAls pfx
-    baseFromItem = S.FISelect (S.Lateral False) baseSel baseSelAls
+    baseSelectAlias = S.Alias $ mkBaseTableAlias sourcePrefix
+    baseFromItem = S.FISelect (S.Lateral False) baseSelect baseSelectAlias
 
     -- function to create a joined from item from two from items
     leftOuterJoin current new =
@@ -746,222 +843,403 @@ baseNodeToSel joinCond baseNode =
     -- this is the from eexp for the final select
     joinedFrom :: S.FromItem
     joinedFrom = foldl' leftOuterJoin baseFromItem $
-                 map objNodeToFromItem (HM.elems objRels) <>
-                 map arrNodeToFromItem (HM.elems arrRels) <>
-                 map computedFieldNodeToFromItem (HM.toList computedFields)
-
-    objNodeToFromItem :: ObjNode -> S.FromItem
-    objNodeToFromItem (ObjNode relMapn relBaseNode) =
-      let als = S.Alias $ _bnPrefix relBaseNode
-          sel = baseNodeToSel (mkJoinCond baseSelAls relMapn) relBaseNode
-      in S.mkLateralFromItem sel als
-
-    arrNodeToFromItem :: ArrNode -> S.FromItem
-    arrNodeToFromItem (ArrNode es colMapn bn) =
-      let sel = arrNodeToSelect bn es (mkJoinCond baseSelAls colMapn)
-          als = S.Alias $ _bnPrefix bn
-      in S.mkLateralFromItem sel als
-
-    computedFieldNodeToFromItem :: (FieldName, CFTableNode) -> S.FromItem
-    computedFieldNodeToFromItem (fld, CFTableNode jsonAggSelect bn) =
-      let internalSel = baseNodeToSel (S.BELit True) bn
-          als = S.Alias $ _bnPrefix bn
-          extr = asJsonAggExtr jsonAggSelect (S.toAlias fld) False Nothing $
-                 _bnOrderBy bn
-          internalSelFrom = S.mkSelFromItem internalSel als
-          sel = S.mkSelect
-                { S.selExtr = pure extr
-                , S.selFrom = Just $ S.FromExp [internalSelFrom]
+                 map objectRelationToFromItem (HM.toList objectRelations) <>
+                 map arrayRelationToFromItem (HM.toList arrayRelations) <>
+                 map arrayConnectionToFromItem (HM.toList arrayConnections) <>
+                 map computedFieldToFromItem (HM.toList computedFields)
+
+
+    objectRelationToFromItem
+      :: (ObjectRelationSource, SelectNode) -> S.FromItem
+    objectRelationToFromItem (objectRelationSource, node) =
+      let ObjectRelationSource _ colMapping source = objectRelationSource
+          alias = S.Alias $ _ssPrefix source
+          select = generateSQLSelect (mkJoinCond baseSelectAlias colMapping) source node
+      in S.mkLateralFromItem select alias
+
+    arrayRelationToFromItem
+      :: (ArrayRelationSource, ArraySelectNode) -> S.FromItem
+    arrayRelationToFromItem (arrayRelationSource, arraySelectNode) =
+      let ArrayRelationSource _ colMapping source = arrayRelationSource
+          alias = S.Alias $ _ssPrefix source
+          select = generateSQLSelectFromArrayNode source arraySelectNode $
+                   mkJoinCond baseSelectAlias colMapping
+      in S.mkLateralFromItem select alias
+
+    arrayConnectionToFromItem
+      :: (ArrayConnectionSource, ArraySelectNode) -> S.FromItem
+    arrayConnectionToFromItem (arrayConnectionSource, arraySelectNode) =
+      let selectWith = connectionToSelectWith baseSelectAlias arrayConnectionSource arraySelectNode
+          alias = S.Alias $ _ssPrefix $ _acsSource arrayConnectionSource
+      in S.FISelectWith (S.Lateral True) selectWith alias
+
+    computedFieldToFromItem
+      :: (ComputedFieldTableSetSource, SelectNode) -> S.FromItem
+    computedFieldToFromItem (computedFieldTableSource, node) =
+      let ComputedFieldTableSetSource fieldName selectTy source = computedFieldTableSource
+          internalSelect = generateSQLSelect (S.BELit True) source node
+          extractor = asJsonAggExtr selectTy (S.toAlias fieldName) PLSQNotRequired $
+                      _ssOrderBy source
+          alias = S.Alias $ _ssPrefix source
+          select = S.mkSelect
+                { S.selExtr = [extractor]
+                , S.selFrom = Just $ S.FromExp [S.mkSelFromItem internalSelect alias]
                 }
-      in S.mkLateralFromItem sel als
-
-data TableSource
-  = TableSource
-    { _tsFrom       :: !SelectFrom
-    , _tsPermission :: !TablePerm
-    , _tsArgs       :: !TableArgs
-    } deriving (Show, Eq, Generic)
-instance Hashable TableSource
-
-
--- data TableSource
---   = TableSource
---     { _tsFrom   :: !S.FromItem
---     , _tsAlias  :: !S.Alias
---     , _tsWhere  :: !S.BoolExp
---     , _tsLimit  :: !(Maybe Int)
---     , _tsOffset :: !(Maybe S.SQLExp)
---     -- , _tsArgs       :: !TableArgs
---     }
---   deriving (Show, Eq, Generic)
-
-
-data BuildState
-  = BuildState
-    { _bsAliasGenerator :: !Int
-    , _bsJoinTree       :: !JoinTree
-    }
-
-type Build = State BuildState
-
--- | this is need in those cases where you need a single row when the table
--- returns multiple
-forceAggregation :: S.SQLExp -> S.SQLExp
-forceAggregation e =
-  S.SEFnApp "coalesce" [ e, S.SEUnsafe "bool_or('true')::text"] Nothing
-
--- | Returns the SQL expression that will construct the response
--- for given field
-buildConnectionFieldExpression
-  :: S.Alias
-  -- ^ The table alias
-  -> ConnectionField S.SQLExp
-  -> Build S.SQLExp
-buildConnectionFieldExpression tableAlias = \case
-  ConnectionTypename typename -> pure $ forceAggregation $ S.SELit typename
-  ConnectionPageInfo fields ->
-    pure $ S.SELit "should be pageinfo"
-  ConnectionEdges fields -> do
-    fieldPairs <- forM fields $ \(fieldAlias, field) -> do
-      fieldExpression <- buildEdgeFieldExpression field
-      pure [S.SELit $ getFieldNameTxt fieldAlias, fieldExpression]
-    pure $ S.applyJsonBuildObj $ concat fieldPairs
+      in S.mkLateralFromItem select alias
+
+generateSQLSelectFromArrayNode
+  :: SelectSource
+  -> ArraySelectNode
+  -> S.BoolExp
+  -> S.Select
+generateSQLSelectFromArrayNode selectSource arraySelectNode joinCondition =
+  S.mkSelect
+  { S.selExtr = topExtractors
+  , S.selFrom = Just $ S.FromExp [selectFrom]
+  }
   where
-    buildEdgeFieldExpression = \case
-      EdgeTypename typename -> pure $ S.SELit typename
-      EdgeCursor -> pure $ S.SELit "will return a cursor"
-      EdgeNode fields -> undefined
-
-data Selector
-  = Selector !S.SQLExp !S.SQLExp
-  deriving (Show, Eq)
-
--- | Returns the SQL expression that will construct the response
--- for given field
-buildTableFieldExpression
-  :: S.Alias
-  -- ^ The table alias
-  -> AnnFldG S.SQLExp
-  -> Build S.SQLExp
-buildTableFieldExpression tableAlias = \case
-  FCol field -> undefined
-  FObj field -> undefined
-  FArr field -> undefined
-  FComputedField field -> undefined
-  FExp typename -> pure $ S.SELit typename
-
-processFields
-  :: ConnectionFields S.SQLExp
-  -> Maybe (NE.NonEmpty (AnnOrderByItemG S.SQLExp))
-  -> Build ()
-processFields = undefined
-
-mkSelectNode
-  :: ConnectionSelect S.SQLExp -> Build (TableSource, SelectNode)
-mkSelectNode = undefined
-
-data SelectNode
-  = SelectNode
-    { _jnColumns  :: !(HM.HashMap S.Alias S.SQLExp)
-    , _jnFrom     :: !S.FromItem
-    , _jnAlias    :: !S.Alias
-    , _jnJoinTree :: !JoinTree
-    , _jnWhere    :: !S.BoolExp
-    , _jnOrderBy  :: !(Maybe S.OrderByExp)
-    , _jnLimit    :: !(Maybe Int)
-    , _jnOffset   :: !(Maybe S.SQLExp)
-    }
-  deriving (Show, Eq)
-
-newtype JoinTree
-  = JoinTree { unJoinTree :: HM.HashMap TableSource SelectNode }
-  deriving (Show, Eq, Semigroup, Monoid)
-
-mkAggSelect :: AnnAggSel -> S.Select
-mkAggSelect annAggSel =
-  prefixNumToAliases $ arrNodeToSelect bn extr $ S.BELit True
+    ArraySelectNode topExtractors selectNode = arraySelectNode
+    selectFrom = S.mkSelFromItem
+                 (generateSQLSelect joinCondition selectSource selectNode) $
+                 S.Alias $ _ssPrefix selectSource
+
+mkAggregateSelect :: AnnAggregateSelect -> S.Select
+mkAggregateSelect annAggSel =
+  let ((selectSource, nodeExtractors, topExtractor), joinTree) =
+        runWriter $ flip runReaderT strfyNum $
+        processAnnAggregateSelect sourcePrefixes rootFieldName annAggSel
+      selectNode = SelectNode nodeExtractors joinTree
+      arrayNode = ArraySelectNode [topExtractor] selectNode
+  in prefixNumToAliases $
+     generateSQLSelectFromArrayNode selectSource arrayNode $ S.BELit True
   where
-    aggSel = AnnRelG rootRelName HM.empty annAggSel
-    rootIden = Iden "root"
-    rootPrefix = Prefixes rootIden rootIden
-    ArrNode extr _ bn =
-      aggSelToArrNode rootPrefix (FieldName "root") aggSel
+    strfyNum = _asnStrfyNum annAggSel
+    rootFieldName = FieldName "root"
+    rootIden = toIden rootFieldName
+    sourcePrefixes = SourcePrefixes rootIden rootIden
 
 mkSQLSelect :: JsonAggSelect -> AnnSimpleSel -> S.Select
 mkSQLSelect jsonAggSelect annSel =
-  prefixNumToAliases $ arrNodeToSelect baseNode extrs $ S.BELit True
+  let permLimitSubQuery = PLSQNotRequired
+      ((selectSource, nodeExtractors), joinTree) =
+        runWriter $ flip runReaderT strfyNum $
+        processAnnSimpleSelect sourcePrefixes rootFldName permLimitSubQuery annSel
+      selectNode = SelectNode nodeExtractors joinTree
+      topExtractor = asJsonAggExtr jsonAggSelect rootFldAls permLimitSubQuery
+                     $ _ssOrderBy selectSource
+      arrayNode = ArraySelectNode [topExtractor] selectNode
+  in prefixNumToAliases $
+     generateSQLSelectFromArrayNode selectSource arrayNode $ S.BELit True
   where
-    permLimit = getPermLimit annSel
-    extrs = pure $ asJsonAggExtr jsonAggSelect rootFldAls False permLimit
-            $ _bnOrderBy baseNode
+    strfyNum = _asnStrfyNum annSel
     rootFldIden = toIden rootFldName
-    rootPrefix = Prefixes rootFldIden rootFldIden
-    baseNode = annSelToBaseNode False rootPrefix rootFldName Nothing annSel
+    sourcePrefixes = SourcePrefixes rootFldIden rootFldIden
     rootFldName = FieldName "root"
     rootFldAls  = S.Alias $ toIden rootFldName
 
-mkConnectionSelectNodeAndExtr
-  :: Prefixes
+mkConnectionSelect :: ConnectionSelect S.SQLExp -> S.SelectWithG S.Select
+mkConnectionSelect connectionSelect =
+  let ((connectionSource, topExtractor, nodeExtractors), joinTree) =
+        runWriter $ flip runReaderT strfyNum $
+        processConnectionSelect sourcePrefixes rootFieldName
+        (S.Alias rootIden) mempty connectionSelect
+      selectNode = ArraySelectNode [topExtractor] $
+                       SelectNode nodeExtractors joinTree
+  in prefixNumToAliasesSelectWith $
+     connectionToSelectWith (S.Alias rootIden) connectionSource selectNode
+  where
+    strfyNum = _asnStrfyNum $ _csSelect connectionSelect
+    rootFieldName = FieldName "root"
+    rootIden = toIden rootFieldName
+    sourcePrefixes = SourcePrefixes rootIden rootIden
+
+-- | First element extractor expression from given record set
+-- For example:- To get first "id" column from given row set,
+-- the function generates the SQL expression AS `(array_agg("id"))[1]`
+mkFirstElementExp :: S.SQLExp -> S.SQLExp
+mkFirstElementExp expIden =
+  -- For Example
+  S.SEArrayIndex (S.SEFnApp "array_agg" [expIden] Nothing) (S.intToSQLExp 1)
+
+-- | Last element extractor expression from given record set.
+-- For example:- To get first "id" column from given row set,
+-- the function generates the SQL expression AS `(array_agg("id"))[array_length(array_agg("id"), 1)]`
+mkLastElementExp :: S.SQLExp -> S.SQLExp
+mkLastElementExp expIden =
+  let arrayExp = S.SEFnApp "array_agg" [expIden] Nothing
+  in S.SEArrayIndex arrayExp $
+     S.SEFnApp "array_length" [arrayExp, S.intToSQLExp 1] Nothing
+
+cursorIden :: Iden
+cursorIden = Iden "__cursor"
+
+startCursorIden :: Iden
+startCursorIden = Iden "__start_cursor"
+
+endCursorIden :: Iden
+endCursorIden = Iden "__end_cursor"
+
+hasPreviousPageIden :: Iden
+hasPreviousPageIden = Iden "__has_previous_page"
+
+hasNextPageIden :: Iden
+hasNextPageIden = Iden "__has_next_page"
+
+pageInfoSelectAliasIden :: Iden
+pageInfoSelectAliasIden = Iden "__page_info"
+
+cursorsSelectAliasIden :: Iden
+cursorsSelectAliasIden = Iden "__cursors_select"
+
+processConnectionSelect
+  :: ( MonadReader Bool m
+     , MonadWriter JoinTree m
+     )
+  => SourcePrefixes
   -> FieldName
-  -> Maybe (NonEmpty PGCol)
+  -> S.Alias
+  -> HM.HashMap PGCol PGCol
   -> ConnectionSelect S.SQLExp
-  -> (BaseNode, S.Extractor)
-mkConnectionSelectNodeAndExtr pfxs fieldAlias primaryKeyColumns connectionSelect =
-  (baseNode, extractor)
+  -> m ( ArrayConnectionSource
+       , S.Extractor
+       , HM.HashMap S.Alias S.SQLExp
+       )
+processConnectionSelect sourcePrefixes fieldAlias relAlias colMapping connectionSelect = do
+  (selectSource, orderByAndDistinctExtrs, maybeOrderByCursor) <-
+    processSelectParams sourcePrefixes fieldAlias similarArrayFields selectFrom
+    permLimitSubQuery tablePermissions tableArgs
+
+  let mkCursorExtractor = (S.Alias cursorIden,) . (`S.SETyAnn` S.textTypeAnn)
+      cursorExtractors = case maybeOrderByCursor of
+        Just orderByCursor -> [mkCursorExtractor orderByCursor]
+        Nothing ->
+          -- Extract primary key columns from base select along with cursor expression.
+          -- Those columns are required to perform connection split via a WHERE clause.
+          mkCursorExtractor primaryKeyColumnsCursor : primaryKeyColumnExtractors
+      orderByExp = _ssOrderBy selectSource
+  (topExtractorExp, exps) <- flip runStateT [] $ processFields orderByExp
+  let topExtractor = S.Extractor topExtractorExp $ Just $ S.Alias fieldIden
+      allExtractors = HM.fromList $ cursorExtractors <> exps <> orderByAndDistinctExtrs
+      arrayConnectionSource = ArrayConnectionSource relAlias
+                              colMapping splitBoolExp slice selectSource
+  pure ( arrayConnectionSource
+       , topExtractor
+       , allExtractors
+       )
   where
-    AnnSelG fields selFrom perm args strfyNum = connectionSelect
+    ConnectionSelect primaryKeyColumns split slice select = connectionSelect
+    AnnSelectG fields selectFrom tablePermissions tableArgs _ = select
     fieldIden = toIden fieldAlias
+    thisPrefix = _pfThis sourcePrefixes
+    permLimitSubQuery = PLSQNotRequired
+
+    primaryKeyColumnsCursor =
+      S.applyJsonBuildObj $ flip concatMap (toList primaryKeyColumns) $
+      \pgColumnInfo ->
+        [ S.SELit $ getPGColTxt $ pgiColumn pgColumnInfo
+        , toJSONableExp False (pgiType pgColumnInfo) False $
+          S.mkQIdenExp (mkBaseTableAlias thisPrefix) $ pgiColumn pgColumnInfo
+        ]
+
+    primaryKeyColumnExtractors =
+      flip map (toList primaryKeyColumns) $
+      \pgColumnInfo ->
+        let pgColumn = pgiColumn pgColumnInfo
+        in ( S.Alias $ mkBaseTableColumnAlias thisPrefix pgColumn
+           , S.mkQIdenExp (mkBaseTableAlias thisPrefix) pgColumn
+           )
+
+    splitBoolExp = flip fmap split $ \splits ->
+      foldr (S.BEBin S.OrOp) (S.BELit False) $
+      flip map (toList splits) $ \s ->
+        let ConnectionSplit kind v (OrderByItemG obTyM obCol _) = s
+            obAlias = mkAnnOrderByAlias thisPrefix fieldAlias similarArrayFields obCol
+            obTy = maybe S.OTAsc unOrderType obTyM
+            compareOp = case (kind, obTy) of
+              (CSKAfter, S.OTAsc)   -> S.SGT
+              (CSKAfter, S.OTDesc)  -> S.SLT
+              (CSKBefore, S.OTAsc)  -> S.SLT
+              (CSKBefore, S.OTDesc) -> S.SGT
+        in S.BECompare compareOp (S.SEIden $ toIden obAlias) v
+
+    similarArrayFields = HM.unions $
+      flip map (map snd fields) $ \case
+      ConnectionTypename{} -> mempty
+      ConnectionPageInfo{} -> mempty
+      ConnectionEdges edges -> HM.unions $
+        flip map (map snd edges) $ \case
+        EdgeTypename{} -> mempty
+        EdgeCursor{} -> mempty
+        EdgeNode annFields ->
+          mkSimilarArrayFields annFields $ _saOrderBy tableArgs
+
+    encodeBase64 t = S.SEFnApp "encode"
+                     [S.SETyAnn t $ S.TypeAnn "bytea", S.SELit "base64"]
+                     Nothing
+
     mkSimpleJsonAgg rowExp ob =
       let jsonAggExp = S.SEFnApp "json_agg" [rowExp] ob
       in S.SEFnApp "coalesce" [jsonAggExp, S.SELit "[]"] Nothing
 
-    baseNode = foldr mergeBaseNodes (mkEmptyBaseNode fieldIden selFrom) nodeList
-    encodeBase64 t = S.SEFnApp "encode" [S.SETyAnn t $ S.TypeAnn "bytea", S.SELit "base64"] Nothing
-
-    extractor = S.Extractor extractorExp $ Just $ S.Alias fieldIden
-    (extractorExp, nodeList) = runWriter $
-      fmap (S.applyJsonBuildObj . concat) $ forM fields $
+    processFields
+      :: ( MonadReader Bool m
+         , MonadWriter JoinTree m
+         , MonadState [(S.Alias, S.SQLExp)] m
+         )
+      => Maybe S.OrderByExp -> m S.SQLExp
+    processFields orderByExp =
+      fmap (S.applyJsonBuildObj . concat) $
+      forM fields $
         \(FieldName fieldText, field) -> (S.SELit fieldText:) . pure <$>
         case field of
-          ConnectionTypename t -> pure $ S.SELit t
-          ConnectionPageInfo f -> pure $ processPageInfoFields f
+          ConnectionTypename t              -> pure $ S.SELit t
+          ConnectionPageInfo pageInfoFields -> pure $ processPageInfoFields pageInfoFields
           ConnectionEdges edges ->
-            -- TODO:- Add order by here
-            fmap (flip mkSimpleJsonAgg Nothing . S.applyJsonBuildObj . concat) $ forM edges $
+            fmap (flip mkSimpleJsonAgg orderByExp . S.applyJsonBuildObj . concat) $ forM edges $
             \(FieldName edgeText, edge) -> (S.SELit edgeText:) . pure <$>
             case edge of
               EdgeTypename t -> pure $ S.SELit t
-              EdgeCursor     -> pure $ encodeBase64 $ S.SEIden (toIden cursorAlias)
+              EdgeCursor     -> pure $ encodeBase64 $ S.SEIden (toIden cursorIden)
               EdgeNode annFields -> do
-                let rootFieldName = FieldName $ "root." <> fieldText <> "." <> edgeText
-                    rootFieldIden = toIden rootFieldName
-                    edgeBaseNode = annSelToBaseNode False pfxs rootFieldName primaryKeyColumns $
-                                   AnnSelG annFields selFrom perm args strfyNum
-                tell [edgeBaseNode]
-                pure $ S.SEIden rootFieldIden
+                let edgeFieldName = FieldName $
+                      getFieldNameTxt fieldAlias <> "." <> fieldText <> "." <> edgeText
+                    edgeFieldIden = toIden edgeFieldName
+                annFieldsExtrExp <- processAnnFields thisPrefix edgeFieldName similarArrayFields annFields
+                modify' (<> [annFieldsExtrExp])
+                pure $ S.SEIden edgeFieldIden
 
     processPageInfoFields infoFields =
       S.applyJsonBuildObj $ flip concatMap infoFields $
-      \(FieldName fieldText, field) -> S.SELit fieldText: case field of
-        PageInfoTypename t      -> pure $ S.SELit t
-        PageInfoHasNextPage     -> pure $ S.SEBool $ S.BELit True
-        PageInfoHasPreviousPage -> pure $ S.SEBool $ S.BELit False
-        PageInfoStartCursor     -> pure $ S.SELit "start cursor"
-        PageInfoEndCursor       -> pure $ S.SELit "end cursor"
-
-connectionSelToArrNode
-  :: Prefixes -> FieldName -> ArrRelConnection S.SQLExp -> ArrNode
-connectionSelToArrNode pfxs als arrRelConnSel =
-  -- TODO:- Get primary key context here.
-  let (baseNode, extr) = mkConnectionSelectNodeAndExtr pfxs als Nothing connSel
-  in ArrNode [extr] colMapping baseNode
+      \(FieldName fieldText, field) -> (:) (S.SELit fieldText) $ pure case field of
+        PageInfoTypename t      -> S.SELit t
+        PageInfoHasNextPage     ->
+          mkSingleFieldSelect (S.SEIden hasNextPageIden) pageInfoSelectAliasIden
+        PageInfoHasPreviousPage ->
+          mkSingleFieldSelect (S.SEIden hasPreviousPageIden) pageInfoSelectAliasIden
+        PageInfoStartCursor     ->
+          encodeBase64 $ mkSingleFieldSelect (S.SEIden startCursorIden) cursorsSelectAliasIden
+        PageInfoEndCursor       ->
+          encodeBase64 $ mkSingleFieldSelect (S.SEIden endCursorIden) cursorsSelectAliasIden
+      where
+        mkSingleFieldSelect field fromIden = S.SESelect
+          S.mkSelect { S.selExtr = [S.Extractor field Nothing]
+                     , S.selFrom = Just $ S.FromExp [S.FIIden fromIden]
+                     }
+
+connectionToSelectWith
+  :: S.Alias
+  -> ArrayConnectionSource
+  -> ArraySelectNode
+  -> S.SelectWithG S.Select
+connectionToSelectWith baseSelectAlias arrayConnectionSource arraySelectNode =
+  let extractionSelect = S.mkSelect
+                         { S.selExtr = topExtractors
+                         , S.selFrom = Just $ S.FromExp [S.FIIden finalSelectIden]
+                         }
+  in S.SelectWith fromBaseSelections extractionSelect
   where
-    AnnRelG _ colMapping connSel = arrRelConnSel
-
-mkConnectionSelect :: Maybe (NonEmpty PGCol) -> ConnectionSelect S.SQLExp -> S.Select
-mkConnectionSelect primaryKeyColumns connectionSelect =
-  let rootFieldName = FieldName "root"
-      rootIden = toIden rootFieldName
-      prefixes = Prefixes rootIden rootIden
-      (baseNode, extractor) = mkConnectionSelectNodeAndExtr prefixes rootFieldName primaryKeyColumns connectionSelect
-  in prefixNumToAliases $ arrNodeToSelect baseNode [extractor] $ S.BELit True
+    ArrayConnectionSource _ columnMapping maybeSplit maybeSlice selectSource =
+      arrayConnectionSource
+    ArraySelectNode topExtractors selectNode = arraySelectNode
+    baseSelectIden = Iden "__base_select"
+    splitSelectIden = Iden "__split_select"
+    sliceSelectIden = Iden "__slice_select"
+    finalSelectIden = Iden "__final_select"
+
+    rowNumberIden = Iden "__row_number"
+    rowNumberExp = S.SEUnsafe "(row_number() over (partition by 1))"
+    startRowNumberIden = Iden "__start_row_number"
+    endRowNumberIden = Iden "__end_row_number"
+
+    startCursorExp = mkFirstElementExp $ S.SEIden cursorIden
+    endCursorExp = mkLastElementExp $ S.SEIden cursorIden
+
+    startRowNumberExp = mkFirstElementExp $ S.SEIden rowNumberIden
+    endRowNumberExp = mkLastElementExp $ S.SEIden rowNumberIden
+
+    fromBaseSelections =
+      let joinCond = mkJoinCond baseSelectAlias columnMapping
+          baseSelectFrom = S.mkSelFromItem
+                           (generateSQLSelect joinCond selectSource selectNode)
+                           $ S.Alias $ _ssPrefix selectSource
+          select =
+            S.mkSelect { S.selExtr = [ S.selectStar
+                                     , S.Extractor rowNumberExp $ Just $ S.Alias rowNumberIden
+                                     ]
+                       , S.selFrom = Just $ S.FromExp [baseSelectFrom]
+                       }
+      in (S.Alias baseSelectIden, select):fromSplitSelection
+
+    mkStarSelect fromIden =
+      S.mkSelect { S.selExtr = [S.selectStar]
+                 , S.selFrom = Just $ S.FromExp [S.FIIden fromIden]
+                 }
+
+    fromSplitSelection = case maybeSplit of
+      Nothing        -> fromSliceSelection baseSelectIden
+      Just splitBool ->
+        let select =
+              (mkStarSelect baseSelectIden){S.selWhere = Just $ S.WhereFrag splitBool}
+        in (S.Alias splitSelectIden, select):fromSliceSelection splitSelectIden
+
+    fromSliceSelection prevSelect = case maybeSlice of
+      Nothing    -> fromFinalSelect prevSelect
+      Just slice ->
+        let select = case slice of
+              SliceFirst limit ->
+                (mkStarSelect prevSelect)
+                {S.selLimit = (Just . S.LimitExp . S.intToSQLExp) limit}
+              SliceLast limit ->
+                let mkRowNumberOrderBy obType =
+                      let orderByItem =
+                            S.OrderByItem (S.SEIden rowNumberIden) (Just obType) Nothing
+                      in S.OrderByExp $ orderByItem NE.:| []
+
+                    sliceLastSelect = (mkStarSelect prevSelect)
+                                      { S.selLimit = (Just . S.LimitExp . S.intToSQLExp) limit
+                                      , S.selOrderBy = Just $ mkRowNumberOrderBy S.OTDesc
+                                      }
+                    sliceLastSelectFrom =
+                      S.mkSelFromItem sliceLastSelect $ S.Alias sliceSelectIden
+                in S.mkSelect { S.selExtr = [S.selectStar]
+                              , S.selFrom = Just $ S.FromExp [sliceLastSelectFrom]
+                              , S.selOrderBy = Just $ mkRowNumberOrderBy S.OTAsc
+                              }
+        in (S.Alias sliceSelectIden, select):fromFinalSelect sliceSelectIden
+
+    fromFinalSelect prevSelect =
+      let select = mkStarSelect prevSelect
+      in (S.Alias finalSelectIden, select):fromCursorSelection
+
+    fromCursorSelection =
+      let extrs = [ S.Extractor startCursorExp $ Just $ S.Alias startCursorIden
+                  , S.Extractor endCursorExp $ Just $ S.Alias endCursorIden
+                  , S.Extractor startRowNumberExp $ Just $ S.Alias startRowNumberIden
+                  , S.Extractor endRowNumberExp $ Just $ S.Alias endRowNumberIden
+                  ]
+          select =
+            S.mkSelect { S.selExtr = extrs
+                       , S.selFrom = Just $ S.FromExp [S.FIIden finalSelectIden]
+                       }
+      in (S.Alias cursorsSelectAliasIden, select):fromPageInfoSelection
+
+    fromPageInfoSelection =
+      let hasPrevPage = S.SEBool $
+            S.mkExists (S.FIIden baseSelectIden) $
+            S.BECompare S.SLT (S.SEIden rowNumberIden) $
+            S.SESelect $ S.mkSelect { S.selFrom = Just $ S.FromExp [S.FIIden cursorsSelectAliasIden]
+                                    , S.selExtr = [S.Extractor (S.SEIden startRowNumberIden) Nothing]
+                                    }
+          hasNextPage = S.SEBool $
+            S.mkExists (S.FIIden baseSelectIden) $
+            S.BECompare S.SGT (S.SEIden rowNumberIden) $
+            S.SESelect $ S.mkSelect { S.selFrom = Just $ S.FromExp [S.FIIden cursorsSelectAliasIden]
+                                    , S.selExtr = [S.Extractor (S.SEIden endRowNumberIden) Nothing]
+                                    }
+
+          select =
+            S.mkSelect { S.selExtr = [ S.Extractor hasPrevPage $ Just $ S.Alias hasPreviousPageIden
+                                     , S.Extractor hasNextPage $ Just $ S.Alias hasNextPageIden
+                                     ]
+                       }
+      in pure (S.Alias pageInfoSelectAliasIden, select)
diff --git a/server/src-lib/Hasura/RQL/DML/Select/Types.hs b/server/src-lib/Hasura/RQL/DML/Select/Types.hs
index 759e1d6b8b201..b78b6ac358639 100644
--- a/server/src-lib/Hasura/RQL/DML/Select/Types.hs
+++ b/server/src-lib/Hasura/RQL/DML/Select/Types.hs
@@ -21,7 +21,8 @@ type SelectQExt = SelectG ExtCol BoolExp Int
 data JsonAggSelect
   = JASMultipleRows
   | JASSingleObject
-  deriving (Show, Eq)
+  deriving (Show, Eq, Generic)
+instance Hashable JsonAggSelect
 
 -- Columns in RQL
 data ExtCol
@@ -50,163 +51,168 @@ instance FromJSON ExtCol where
     , "object (relationship)"
     ]
 
-data AnnAggOrdBy
+data AnnAggregateOrderBy
   = AAOCount
-  | AAOOp !T.Text !PGCol
+  | AAOOp !T.Text !PGColumnInfo
   deriving (Show, Eq, Generic)
-instance Hashable AnnAggOrdBy
+instance Hashable AnnAggregateOrderBy
 
-data AnnObColG v
-  = AOCPG !PGCol
-  | AOCObj !RelInfo !(AnnBoolExp v) !(AnnObColG v)
-  | AOCAgg !RelInfo !(AnnBoolExp v) !AnnAggOrdBy
-  deriving (Show, Eq, Generic)
-instance (Hashable v) => Hashable (AnnObColG v)
+data AnnOrderByElementG v
+  = AOCColumn !PGColumnInfo
+  | AOCObjectRelation !RelInfo !v !(AnnOrderByElementG v)
+  | AOCArrayAggregation !RelInfo !v !AnnAggregateOrderBy
+  deriving (Show, Eq, Generic, Functor)
+instance (Hashable v) => Hashable (AnnOrderByElementG v)
 
-traverseAnnObCol
+type AnnOrderByElement v = AnnOrderByElementG (AnnBoolExp v)
+
+traverseAnnOrderByElement
   :: (Applicative f)
-  => (a -> f b) -> AnnObColG a -> f (AnnObColG b)
-traverseAnnObCol f = \case
-  AOCPG pgColInfo -> pure $ AOCPG pgColInfo
-  AOCObj relInfo annBoolExp annObCol ->
-    AOCObj relInfo
+  => (a -> f b) -> AnnOrderByElement a -> f (AnnOrderByElement b)
+traverseAnnOrderByElement f = \case
+  AOCColumn pgColInfo -> pure $ AOCColumn pgColInfo
+  AOCObjectRelation relInfo annBoolExp annObCol ->
+    AOCObjectRelation relInfo
     <$> traverseAnnBoolExp f annBoolExp
-    <*> traverseAnnObCol f annObCol
-  AOCAgg relInfo annBoolExp annAggOb ->
-    AOCAgg relInfo
+    <*> traverseAnnOrderByElement f annObCol
+  AOCArrayAggregation relInfo annBoolExp annAggOb ->
+    AOCArrayAggregation relInfo
     <$> traverseAnnBoolExp f annBoolExp
     <*> pure annAggOb
 
-type AnnObCol = AnnObColG S.SQLExp
-
-type AnnOrderByItemG v = OrderByItemG (AnnObColG v)
+type AnnOrderByItemG v = OrderByItemG (AnnOrderByElement v)
 
 traverseAnnOrderByItem
   :: (Applicative f)
   => (a -> f b) -> AnnOrderByItemG a -> f (AnnOrderByItemG b)
 traverseAnnOrderByItem f =
-  traverse (traverseAnnObCol f)
+  traverse (traverseAnnOrderByElement f)
 
 type AnnOrderByItem = AnnOrderByItemG S.SQLExp
 
-data AnnRelG a
-  = AnnRelG
-  { aarName    :: !RelName -- Relationship name
-  , aarMapping :: !(HashMap PGCol PGCol) -- Column of left table to join with
-  , aarAnnSel  :: !a -- Current table. Almost ~ to SQL Select
+type OrderByItemExp =
+  OrderByItemG (AnnOrderByElement S.SQLExp, (S.Alias, S.SQLExp))
+
+data AnnRelationSelectG a
+  = AnnRelationSelectG
+  { aarRelationshipName :: !RelName -- Relationship name
+  , aarColumnMapping    :: !(HashMap PGCol PGCol) -- Column of left table to join with
+  , aarAnnSelect        :: !a -- Current table. Almost ~ to SQL Select
   } deriving (Show, Eq, Functor, Foldable, Traversable)
 
-type ObjSelG v = AnnRelG (AnnSimpleSelG v)
-type ObjSel = ObjSelG S.SQLExp
+type ObjectRelationSelectG v = AnnRelationSelectG (AnnSimpleSelG v)
+type ObjectRelationSelect = ObjectRelationSelectG S.SQLExp
 
-type ArrRelG v = AnnRelG (AnnSimpleSelG v)
-type ArrRelAggG v = AnnRelG (AnnAggSelG v)
-type ArrRelConnection v = AnnRelG (ConnectionSelect v)
-type ArrRelAgg = ArrRelAggG S.SQLExp
+type ArrayRelationSelectG v = AnnRelationSelectG (AnnSimpleSelG v)
+type ArrayAggregateSelectG v = AnnRelationSelectG (AnnAggregateSelectG v)
+type ArrayConnectionSelect v = AnnRelationSelectG (ConnectionSelect v)
+type ArrayAggregateSelect = ArrayAggregateSelectG S.SQLExp
 
-data ComputedFieldScalarSel v
-  = ComputedFieldScalarSel
+data ComputedFieldScalarSelect v
+  = ComputedFieldScalarSelect
   { _cfssFunction  :: !QualifiedFunction
   , _cfssArguments :: !(FunctionArgsExpTableRow v)
   , _cfssType      :: !PGScalarType
-  , _cfssColumnOp  :: !(Maybe ColOp)
+  , _cfssColumnOp  :: !(Maybe ColumnOp)
   } deriving (Show, Eq, Functor, Foldable, Traversable)
 
-data ComputedFieldSel v
-  = CFSScalar !(ComputedFieldScalarSel v)
+data ComputedFieldSelect v
+  = CFSScalar !(ComputedFieldScalarSelect v)
   | CFSTable !JsonAggSelect !(AnnSimpleSelG v)
   deriving (Show, Eq)
 
-traverseComputedFieldSel
+traverseComputedFieldSelect
   :: (Applicative f)
   => (v -> f w)
-  -> ComputedFieldSel v -> f (ComputedFieldSel w)
-traverseComputedFieldSel fv = \case
+  -> ComputedFieldSelect v -> f (ComputedFieldSelect w)
+traverseComputedFieldSelect fv = \case
   CFSScalar scalarSel -> CFSScalar <$> traverse fv scalarSel
-  CFSTable b tableSel -> CFSTable b <$> traverseAnnSimpleSel fv tableSel
+  CFSTable b tableSel -> CFSTable b <$> traverseAnnSimpleSelect fv tableSel
 
 type Fields a = [(FieldName, a)]
 
-data ArrSelG v
-  = ASSimple !(ArrRelG v)
-  | ASAgg !(ArrRelAggG v)
-  | ASConnection !(ArrRelConnection v)
+data ArraySelectG v
+  = ASSimple !(ArrayRelationSelectG v)
+  | ASAggregate !(ArrayAggregateSelectG v)
+  | ASConnection !(ArrayConnectionSelect v)
   deriving (Show, Eq)
 
-traverseArrSel
+traverseArraySelect
   :: (Applicative f)
   => (a -> f b)
-  -> ArrSelG a
-  -> f (ArrSelG b)
-traverseArrSel f = \case
-  ASSimple arrRel -> ASSimple <$> traverse (traverseAnnSimpleSel f) arrRel
-  ASAgg arrRelAgg -> ASAgg <$> traverse (traverseAnnAggSel f) arrRelAgg
+  -> ArraySelectG a
+  -> f (ArraySelectG b)
+traverseArraySelect f = \case
+  ASSimple arrRel ->
+    ASSimple <$> traverse (traverseAnnSimpleSelect f) arrRel
+  ASAggregate arrRelAgg ->
+    ASAggregate <$> traverse (traverseAnnAggregateSelect f) arrRelAgg
   ASConnection relConnection ->
     ASConnection <$> traverse (traverseConnectionSelect f) relConnection
 
-type ArrSel = ArrSelG S.SQLExp
+type ArraySelect = ArraySelectG S.SQLExp
 
-type ArrSelFldsG v = Fields (ArrSelG v)
+type ArraySelectFieldsG v = Fields (ArraySelectG v)
 
-data ColOp
-  = ColOp
+data ColumnOp
+  = ColumnOp
   { _colOp  :: S.SQLOp
   , _colExp :: S.SQLExp
   } deriving (Show, Eq)
 
-data AnnColField
-  = AnnColField
+data AnnColumnField
+  = AnnColumnField
   { _acfInfo   :: !PGColumnInfo
   , _acfAsText :: !Bool
   -- ^ If this field is 'True', columns are explicitly casted to @text@ when fetched, which avoids
   -- an issue that occurs because we don’t currently have proper support for array types. See
   -- https://github.com/hasura/graphql-engine/pull/3198 for more details.
-  , _acfOp     :: !(Maybe ColOp)
+  , _acfOp     :: !(Maybe ColumnOp)
   } deriving (Show, Eq)
 
-data AnnFldG v
-  = FCol !AnnColField
-  | FObj !(ObjSelG v)
-  | FArr !(ArrSelG v)
-  | FComputedField !(ComputedFieldSel v)
-  | FExp !T.Text
+data AnnFieldG v
+  = AFColumn !AnnColumnField
+  | AFObjectRelation !(ObjectRelationSelectG v)
+  | AFArrayRelation !(ArraySelectG v)
+  | AFComputedField !(ComputedFieldSelect v)
+  | AFExpression !T.Text
   deriving (Show, Eq)
 
-mkAnnColField :: PGColumnInfo -> Maybe ColOp -> AnnFldG v
-mkAnnColField ci colOpM =
-  FCol $ AnnColField ci False colOpM
+mkAnnColumnField :: PGColumnInfo -> Maybe ColumnOp -> AnnFieldG v
+mkAnnColumnField ci colOpM =
+  AFColumn $ AnnColumnField ci False colOpM
 
-mkAnnColFieldAsText :: PGColumnInfo -> AnnFldG v
-mkAnnColFieldAsText ci =
-  FCol $ AnnColField ci True Nothing
+mkAnnColumnFieldAsText :: PGColumnInfo -> AnnFieldG v
+mkAnnColumnFieldAsText ci =
+  AFColumn $ AnnColumnField ci True Nothing
 
-traverseAnnFld
+traverseAnnField
   :: (Applicative f)
-  => (a -> f b) -> AnnFldG a -> f (AnnFldG b)
-traverseAnnFld f = \case
-  FCol colFld -> pure $ FCol colFld
-  FObj sel -> FObj <$> traverse (traverseAnnSimpleSel f) sel
-  FArr sel -> FArr <$> traverseArrSel f sel
-  FComputedField sel -> FComputedField <$> traverseComputedFieldSel f sel
-  FExp t -> FExp <$> pure t
-
-type AnnFld = AnnFldG S.SQLExp
-
-data TableArgsG v
-  = TableArgs
-  { _taWhere    :: !(Maybe (AnnBoolExp v))
-  , _taOrderBy  :: !(Maybe (NE.NonEmpty (AnnOrderByItemG v)))
-  , _taLimit    :: !(Maybe Int)
-  , _taOffset   :: !(Maybe S.SQLExp)
-  , _taDistCols :: !(Maybe (NE.NonEmpty PGCol))
+  => (a -> f b) -> AnnFieldG a -> f (AnnFieldG b)
+traverseAnnField f = \case
+  AFColumn colFld -> pure $ AFColumn colFld
+  AFObjectRelation sel -> AFObjectRelation <$> traverse (traverseAnnSimpleSelect f) sel
+  AFArrayRelation sel -> AFArrayRelation <$> traverseArraySelect f sel
+  AFComputedField sel -> AFComputedField <$> traverseComputedFieldSelect f sel
+  AFExpression t -> AFExpression <$> pure t
+
+type AnnField = AnnFieldG S.SQLExp
+
+data SelectArgsG v
+  = SelectArgs
+  { _saWhere    :: !(Maybe (AnnBoolExp v))
+  , _saOrderBy  :: !(Maybe (NE.NonEmpty (AnnOrderByItemG v)))
+  , _saLimit    :: !(Maybe Int)
+  , _saOffset   :: !(Maybe S.SQLExp)
+  , _saDistinct :: !(Maybe (NE.NonEmpty PGCol))
   } deriving (Show, Eq, Generic)
-instance (Hashable v) => Hashable (TableArgsG v)
+instance (Hashable v) => Hashable (SelectArgsG v)
 
-traverseTableArgs
+traverseSelectArgs
   :: (Applicative f)
-  => (a -> f b) -> TableArgsG a -> f (TableArgsG b)
-traverseTableArgs f (TableArgs wh ordBy lmt ofst distCols) =
-  TableArgs
+  => (a -> f b) -> SelectArgsG a -> f (SelectArgsG b)
+traverseSelectArgs f (SelectArgs wh ordBy lmt ofst distCols) =
+  SelectArgs
   <$> traverse (traverseAnnBoolExp f) wh
   -- traversing through maybe -> nonempty -> annorderbyitem
   <*> traverse (traverse (traverseAnnOrderByItem f)) ordBy
@@ -214,43 +220,43 @@ traverseTableArgs f (TableArgs wh ordBy lmt ofst distCols) =
   <*> pure ofst
   <*> pure distCols
 
-type TableArgs = TableArgsG S.SQLExp
+type SelectArgs = SelectArgsG S.SQLExp
 
-noTableArgs :: TableArgsG v
-noTableArgs = TableArgs Nothing Nothing Nothing Nothing Nothing
+noSelectArgs :: SelectArgsG v
+noSelectArgs = SelectArgs Nothing Nothing Nothing Nothing Nothing
 
 data PGColFld
   = PCFCol !PGCol
   | PCFExp !T.Text
   deriving (Show, Eq)
 
-type ColFlds = Fields PGColFld
+type ColumnFields = Fields PGColFld
 
-data AggOp
-  = AggOp
-  { _aoOp   :: !T.Text
-  , _aoFlds :: !ColFlds
+data AggregateOp
+  = AggregateOp
+  { _aoOp     :: !T.Text
+  , _aoFields :: !ColumnFields
   } deriving (Show, Eq)
 
-data AggFld
+data AggregateField
   = AFCount !S.CountType
-  | AFOp !AggOp
+  | AFOp !AggregateOp
   | AFExp !T.Text
   deriving (Show, Eq)
 
-type AggFlds = Fields AggFld
-type AnnFldsG v = Fields (AnnFldG v)
+type AggregateFields = Fields AggregateField
+type AnnFieldsG v = Fields (AnnFieldG v)
 
-traverseAnnFlds
+traverseAnnFields
   :: (Applicative f)
-  => (a -> f b) -> AnnFldsG a -> f (AnnFldsG b)
-traverseAnnFlds f = traverse (traverse (traverseAnnFld f))
+  => (a -> f b) -> AnnFieldsG a -> f (AnnFieldsG b)
+traverseAnnFields f = traverse (traverse (traverseAnnField f))
 
-type AnnFlds = AnnFldsG S.SQLExp
+type AnnFields = AnnFieldsG S.SQLExp
 
-data TableAggFldG v
-  = TAFAgg !AggFlds
-  | TAFNodes !(AnnFldsG v)
+data TableAggregateFieldG v
+  = TAFAgg !AggregateFields
+  | TAFNodes !(AnnFieldsG v)
   | TAFExp !T.Text
   deriving (Show, Eq)
 
@@ -266,7 +272,7 @@ type PageInfoFields = Fields PageInfoField
 data EdgeField v
   = EdgeTypename !Text
   | EdgeCursor
-  | EdgeNode !(AnnFldsG v)
+  | EdgeNode !(AnnFieldsG v)
   deriving (Show, Eq)
 type EdgeFields v = Fields (EdgeField v)
 
@@ -276,7 +282,7 @@ traverseEdgeField
 traverseEdgeField f = \case
   EdgeTypename t  -> pure $ EdgeTypename t
   EdgeCursor      -> pure EdgeCursor
-  EdgeNode fields -> EdgeNode <$> traverseAnnFlds f fields
+  EdgeNode fields -> EdgeNode <$> traverseAnnFields f fields
 
 data ConnectionField v
   = ConnectionTypename !Text
@@ -294,17 +300,17 @@ traverseConnectionField f = \case
   ConnectionEdges fields ->
     ConnectionEdges <$> traverse (traverse (traverseEdgeField f)) fields
 
-traverseTableAggFld
+traverseTableAggregateField
   :: (Applicative f)
-  => (a -> f b) -> TableAggFldG a -> f (TableAggFldG b)
-traverseTableAggFld f = \case
+  => (a -> f b) -> TableAggregateFieldG a -> f (TableAggregateFieldG b)
+traverseTableAggregateField f = \case
   TAFAgg aggFlds -> pure $ TAFAgg aggFlds
-  TAFNodes annFlds -> TAFNodes <$> traverseAnnFlds f annFlds
+  TAFNodes annFlds -> TAFNodes <$> traverseAnnFields f annFlds
   TAFExp t -> pure $ TAFExp t
 
-type TableAggFld = TableAggFldG S.SQLExp
-type TableAggFldsG v = Fields (TableAggFldG v)
-type TableAggFlds = TableAggFldsG S.SQLExp
+type TableAggregateField = TableAggregateFieldG S.SQLExp
+type TableAggregateFieldsG v = Fields (TableAggregateFieldG v)
+type TableAggregateFields = TableAggregateFieldsG S.SQLExp
 
 data ArgumentExp a
   = AETableRow !(Maybe Iden) -- ^ table row accessor
@@ -349,56 +355,89 @@ noTablePermissions =
 
 type TablePerm = TablePermG S.SQLExp
 
-data AnnSelG a v
-  = AnnSelG
+data AnnSelectG a v
+  = AnnSelectG
   { _asnFields   :: !a
   , _asnFrom     :: !(SelectFromG v)
   , _asnPerm     :: !(TablePermG v)
-  , _asnArgs     :: !(TableArgsG v)
+  , _asnArgs     :: !(SelectArgsG v)
   , _asnStrfyNum :: !Bool
   } deriving (Show, Eq)
 
-getPermLimit :: AnnSelG a v -> Maybe Int
-getPermLimit = _tpLimit . _asnPerm
-
-traverseAnnSimpleSel
+traverseAnnSimpleSelect
   :: (Applicative f)
   => (a -> f b)
   -> AnnSimpleSelG a -> f (AnnSimpleSelG b)
-traverseAnnSimpleSel f = traverseAnnSel (traverseAnnFlds f) f
+traverseAnnSimpleSelect f = traverseAnnSelect (traverseAnnFields f) f
 
-traverseAnnAggSel
+traverseAnnAggregateSelect
   :: (Applicative f)
   => (a -> f b)
-  -> AnnAggSelG a -> f (AnnAggSelG b)
-traverseAnnAggSel f =
-  traverseAnnSel (traverse (traverse (traverseTableAggFld f))) f
+  -> AnnAggregateSelectG a -> f (AnnAggregateSelectG b)
+traverseAnnAggregateSelect f =
+  traverseAnnSelect (traverse (traverse (traverseTableAggregateField f))) f
 
-traverseAnnSel
+traverseAnnSelect
   :: (Applicative f)
   => (a -> f b) -> (v -> f w)
-  -> AnnSelG a v -> f (AnnSelG b w)
-traverseAnnSel f1 f2 (AnnSelG flds tabFrom perm args strfyNum) =
-  AnnSelG
+  -> AnnSelectG a v -> f (AnnSelectG b w)
+traverseAnnSelect f1 f2 (AnnSelectG flds tabFrom perm args strfyNum) =
+  AnnSelectG
   <$> f1 flds
   <*> traverse f2 tabFrom
   <*> traverseTablePerm f2 perm
-  <*> traverseTableArgs f2 args
+  <*> traverseSelectArgs f2 args
   <*> pure strfyNum
 
-type AnnSimpleSelG v = AnnSelG (AnnFldsG v) v
+type AnnSimpleSelG v = AnnSelectG (AnnFieldsG v) v
 type AnnSimpleSel = AnnSimpleSelG S.SQLExp
 
-type AnnAggSelG v = AnnSelG (TableAggFldsG v) v
-type AnnAggSel = AnnAggSelG S.SQLExp
+type AnnAggregateSelectG v = AnnSelectG (TableAggregateFieldsG v) v
+type AnnAggregateSelect = AnnAggregateSelectG S.SQLExp
+
+data ConnectionSlice
+  = SliceFirst !Int
+  | SliceLast !Int
+  deriving (Show, Eq, Generic)
+instance Hashable ConnectionSlice
+
+data ConnectionSplitKind
+  = CSKBefore
+  | CSKAfter
+  deriving (Show, Eq, Generic)
+instance Hashable ConnectionSplitKind
+
+data ConnectionSplit v
+  = ConnectionSplit
+  { _csKind    :: !ConnectionSplitKind
+  , _csValue   :: !v
+  , _csOrderBy :: !(OrderByItemG (AnnOrderByElementG ()))
+  } deriving (Show, Eq, Functor, Generic, Foldable, Traversable)
+instance (Hashable v) => Hashable (ConnectionSplit v)
+
+traverseConnectionSplit
+  :: (Applicative f)
+  => (a -> f b) -> ConnectionSplit a -> f (ConnectionSplit b)
+traverseConnectionSplit f (ConnectionSplit k v ob) =
+  ConnectionSplit k <$> f v <*> pure ob
+
+data ConnectionSelect v
+  = ConnectionSelect
+  { _csPrimaryKeyColumns :: !(NE.NonEmpty PGColumnInfo)
+  , _csSplit             :: !(Maybe (NE.NonEmpty (ConnectionSplit v)))
+  , _csSlice             :: !(Maybe ConnectionSlice)
+  , _csSelect            :: !(AnnSelectG (ConnectionFields v) v)
+  } deriving (Show, Eq)
 
-type ConnectionSelect v = AnnSelG (ConnectionFields v) v
 traverseConnectionSelect
   :: (Applicative f)
   => (a -> f b)
   -> ConnectionSelect a -> f (ConnectionSelect b)
-traverseConnectionSelect f =
-  traverseAnnSel (traverse (traverse (traverseConnectionField f))) f
+traverseConnectionSelect f (ConnectionSelect pkCols cSplit cSlice sel) =
+  ConnectionSelect pkCols
+  <$> traverse (traverse (traverseConnectionSplit f)) cSplit
+  <*> pure cSlice
+  <*> traverseAnnSelect (traverse (traverse (traverseConnectionField f))) f sel
 
 data FunctionArgsExpG a
   = FunctionArgsExp
@@ -429,111 +468,102 @@ insertFunctionArg argName index value (FunctionArgsExp positional named) =
   where
     insertAt i a = toList . Seq.insertAt i a . Seq.fromList
 
-data BaseNode
-  = BaseNode
-  { _bnPrefix              :: !Iden
-  , _bnDistinct            :: !(Maybe S.DistinctExpr)
-  , _bnFrom                :: !S.FromItem
-  , _bnWhere               :: !S.BoolExp
-  , _bnOrderBy             :: !(Maybe S.OrderByExp)
-  , _bnLimit               :: !(Maybe Int)
-  , _bnOffset              :: !(Maybe S.SQLExp)
-
-  , _bnExtrs               :: !(HM.HashMap S.Alias S.SQLExp)
-  , _bnObjs                :: !(HM.HashMap RelName ObjNode)
-  , _bnArrs                :: !(HM.HashMap S.Alias ArrNode)
-  , _bnComputedFieldTables :: !(HM.HashMap FieldName CFTableNode)
-  } deriving (Show, Eq)
-
-mergeBaseNodes :: BaseNode -> BaseNode -> BaseNode
-mergeBaseNodes lNodeDet rNodeDet =
-  BaseNode pfx dExp f whr ordBy limit offset
-  (HM.union lExtrs rExtrs)
-  (HM.unionWith mergeObjNodes lObjs rObjs)
-  (HM.unionWith mergeArrNodes lArrs rArrs)
-  (HM.unionWith mergeCFTableNodes lCFTables rCFTables)
-  where
-    BaseNode pfx dExp f whr ordBy limit offset lExtrs lObjs lArrs lCFTables
-      = lNodeDet
-    BaseNode _   _    _ _   _     _     _      rExtrs rObjs rArrs rCFTables
-      = rNodeDet
-
-data OrderByNode
-  = OBNNothing
-  | OBNObjNode !RelName !ObjNode
-  | OBNArrNode !S.Alias !ArrNode
-  deriving (Show, Eq)
+data SourcePrefixes
+  = SourcePrefixes
+  { _pfThis :: !Iden -- ^ Current source prefix
+  , _pfBase :: !Iden
+  -- ^ Base table source row identifier to generate
+  -- the table's column identifiers for computed field
+  -- function input parameters
+  } deriving (Show, Eq, Generic)
+instance Hashable SourcePrefixes
+
+data SelectSource
+  = SelectSource
+  { _ssPrefix   :: !Iden
+  , _ssFrom     :: !S.FromItem
+  , _ssDistinct :: !(Maybe S.DistinctExpr)
+  , _ssWhere    :: !S.BoolExp
+  , _ssOrderBy  :: !(Maybe S.OrderByExp)
+  , _ssLimit    :: !(Maybe Int)
+  , _ssOffset   :: !(Maybe S.SQLExp)
+  } deriving (Show, Eq, Generic)
+instance Hashable SelectSource
 
-data ArrRelCtxG v
-  = ArrRelCtx
-  { aacFields    :: !(ArrSelFldsG v)
-  , aacAggOrdBys :: ![RelName]
+data SelectNode
+  = SelectNode
+  { _snExtractors :: !(HM.HashMap S.Alias S.SQLExp)
+  , _snJoinTree   :: !JoinTree
   } deriving (Show, Eq)
 
-type ArrRelCtx = ArrRelCtxG S.SQLExp
+instance Semigroup SelectNode where
+  SelectNode lExtrs lJoinTree <> SelectNode rExtrs rJoinTree =
+    SelectNode (lExtrs <> rExtrs) (lJoinTree <> rJoinTree)
 
-emptyArrRelCtx :: ArrRelCtxG a
-emptyArrRelCtx = ArrRelCtx [] []
-
-data ArrNodeItemG v
-  = ANIField !(FieldName, ArrSelG v)
-  | ANIAggOrdBy !RelName
-  deriving (Show, Eq)
+data ObjectRelationSource
+  = ObjectRelationSource
+  { _orsRelationshipName :: !RelName
+  , _orsRelationMapping  :: !(HM.HashMap PGCol PGCol)
+  , _orsSelectSource     :: !SelectSource
+  } deriving (Show, Eq, Generic)
+instance Hashable ObjectRelationSource
 
-type ArrNodeItem = ArrNodeItemG S.SQLExp
+data ArrayRelationSource
+  = ArrayRelationSource
+  { _arsAlias           :: !S.Alias
+  , _arsRelationMapping :: !(HM.HashMap PGCol PGCol)
+  , _arsSelectSource    :: !SelectSource
+  } deriving (Show, Eq, Generic)
+instance Hashable ArrayRelationSource
 
-data ObjNode
-  = ObjNode
-  { _rnRelMapping :: !(HashMap PGCol PGCol)
-  , _rnNodeDet    :: !BaseNode
+data ArraySelectNode
+  = ArraySelectNode
+  { _asnTopExtractors :: ![S.Extractor]
+  , _asnSelectNode    :: !SelectNode
   } deriving (Show, Eq)
 
-mergeObjNodes :: ObjNode -> ObjNode -> ObjNode
-mergeObjNodes lNode rNode =
-  ObjNode colMapping $ mergeBaseNodes lBN rBN
-  where
-    ObjNode colMapping lBN = lNode
-    ObjNode _          rBN = rNode
-
--- simple array select, aggregate select and order by
--- nodes differ in extractors
-data ArrNode
-  = ArrNode
-  { _anExtr       :: ![S.Extractor]
-  , _anRelMapping :: !(HashMap PGCol PGCol)
-  , _anNodeDet    :: !BaseNode
-  } deriving (Show, Eq)
+instance Semigroup ArraySelectNode where
+  ArraySelectNode lTopExtrs lSelNode <> ArraySelectNode rTopExtrs rSelNode =
+    ArraySelectNode (lTopExtrs <> rTopExtrs) (lSelNode <> rSelNode)
 
-mergeArrNodes :: ArrNode -> ArrNode -> ArrNode
-mergeArrNodes lNode rNode =
-  ArrNode (lExtrs `union` rExtrs) colMapping $
-  mergeBaseNodes lBN rBN
-  where
-    ArrNode lExtrs colMapping lBN = lNode
-    ArrNode rExtrs _          rBN = rNode
-
-data ArrNodeInfo
-  = ArrNodeInfo
-  { _aniAlias            :: !S.Alias
-  , _aniPrefix           :: !Iden
-  , _aniSubQueryRequired :: !Bool
-  } deriving (Show, Eq)
+data ComputedFieldTableSetSource
+  = ComputedFieldTableSetSource
+  { _cftssFieldName    :: !FieldName
+  , _cftssSelectType   :: !JsonAggSelect
+  , _cftssSelectSource :: !SelectSource
+  } deriving (Show, Eq, Generic)
+instance Hashable ComputedFieldTableSetSource
+
+data ArrayConnectionSource
+  = ArrayConnectionSource
+  { _acsAlias           :: !S.Alias
+  , _acsRelationMapping :: !(HM.HashMap PGCol PGCol)
+  , _acsSplitFilter     :: !(Maybe S.BoolExp)
+  , _acsSlice           :: !(Maybe ConnectionSlice)
+  , _acsSource          :: !SelectSource
+  } deriving (Show, Eq, Generic)
 
--- | Node for computed field returning setof <table>
-data CFTableNode
-  = CFTableNode
-  { _ctnSelectType :: !JsonAggSelect
-  , _ctnNode       :: !BaseNode
+instance Hashable ArrayConnectionSource
+
+data JoinTree
+  = JoinTree
+  { _jtObjectRelations        :: !(HM.HashMap ObjectRelationSource SelectNode)
+  , _jtArrayRelations         :: !(HM.HashMap ArrayRelationSource ArraySelectNode)
+  , _jtArrayConnections       :: !(HM.HashMap ArrayConnectionSource ArraySelectNode)
+  , _jtComputedFieldTableSets :: !(HM.HashMap ComputedFieldTableSetSource SelectNode)
   } deriving (Show, Eq)
 
-mergeCFTableNodes :: CFTableNode -> CFTableNode -> CFTableNode
-mergeCFTableNodes lNode rNode =
-  CFTableNode
-  (_ctnSelectType rNode)
-  (mergeBaseNodes (_ctnNode lNode) (_ctnNode rNode))
+instance Semigroup JoinTree where
+  JoinTree lObjs lArrs lArrConns lCfts <> JoinTree rObjs rArrs rArrConns rCfts =
+    JoinTree (HM.unionWith (<>) lObjs rObjs)
+             (HM.unionWith (<>) lArrs rArrs)
+             (HM.unionWith (<>) lArrConns rArrConns)
+             (HM.unionWith (<>) lCfts rCfts)
 
-data Prefixes
-  = Prefixes
-  { _pfThis :: !Iden -- Current node prefix
-  , _pfBase :: !Iden -- Base table row identifier for computed field function
-  } deriving (Show, Eq)
+instance Monoid JoinTree where
+  mempty = JoinTree mempty mempty mempty mempty
+
+data PermissionLimitSubQuery
+  = PLSQRequired !Int -- ^ Permission limit
+  | PLSQNotRequired
+  deriving (Show, Eq)
diff --git a/server/src-lib/Hasura/RQL/Types/Common.hs b/server/src-lib/Hasura/RQL/Types/Common.hs
index 9c70b544826b7..b685bc9df7473 100644
--- a/server/src-lib/Hasura/RQL/Types/Common.hs
+++ b/server/src-lib/Hasura/RQL/Types/Common.hs
@@ -150,6 +150,7 @@ newtype FieldName
   deriving ( Show, Eq, Ord, Hashable, FromJSON, ToJSON
            , FromJSONKey, ToJSONKey, Lift, Data, Generic
            , IsString, Arbitrary, NFData, Cacheable
+           , Semigroup
            )
 
 instance IsIden FieldName where
diff --git a/server/src-lib/Hasura/SQL/DML.hs b/server/src-lib/Hasura/SQL/DML.hs
index 8e1b3a67117f9..7e291559bfda1 100644
--- a/server/src-lib/Hasura/SQL/DML.hs
+++ b/server/src-lib/Hasura/SQL/DML.hs
@@ -59,7 +59,7 @@ instance ToSQL OffsetExp where
     "OFFSET" <-> toSQL se
 
 newtype OrderByExp
-  = OrderByExp [OrderByItem]
+  = OrderByExp (NonEmpty OrderByItem)
   deriving (Show, Eq, NFData, Data, Cacheable, Hashable)
 
 data OrderByItem
@@ -100,7 +100,7 @@ instance ToSQL NullsOrder where
 
 instance ToSQL OrderByExp where
   toSQL (OrderByExp l) =
-    "ORDER BY" <-> (", " <+> l)
+    "ORDER BY" <-> (", " <+> toList l)
 
 newtype GroupByExp
   = GroupByExp [SQLExp]
@@ -306,6 +306,7 @@ data SQLExp
   | SEBool !BoolExp
   | SEExcluded !Iden
   | SEArray ![SQLExp]
+  | SEArrayIndex !SQLExp !SQLExp
   | SETuple !TupleExp
   | SECount !CountType
   | SENamedArg !Iden !SQLExp
@@ -375,6 +376,9 @@ instance ToSQL SQLExp where
                          <> toSQL i
   toSQL (SEArray exps) = "ARRAY" <> TB.char '['
                          <> (", " <+> exps) <> TB.char ']'
+  toSQL (SEArrayIndex arrayExp indexExp) =
+    paren (toSQL arrayExp)
+    <> TB.char '[' <> toSQL indexExp <> TB.char ']'
   toSQL (SETuple tup) = toSQL tup
   toSQL (SECount ty) = "COUNT" <> paren (toSQL ty)
   -- https://www.postgresql.org/docs/current/sql-syntax-calling-funcs.html
@@ -516,6 +520,7 @@ data FromItem
   | FIFunc !FunctionExp
   | FIUnnest ![SQLExp] !Alias ![SQLExp]
   | FISelect !Lateral !Select !Alias
+  | FISelectWith !Lateral !(SelectWithG Select) !Alias
   | FIValues !ValuesExp !Alias !(Maybe [PGCol])
   | FIJoin !JoinExpr
   deriving (Show, Eq, Generic, Data)
@@ -544,6 +549,8 @@ instance ToSQL FromItem where
     "UNNEST" <> paren (", " <+> args) <-> toSQL als <> paren (", " <+> cols)
   toSQL (FISelect mla sel al) =
     toSQL mla <-> paren (toSQL sel) <-> toSQL al
+  toSQL (FISelectWith mla selWith al) =
+    toSQL mla <-> paren (toSQL selWith) <-> toSQL al
   toSQL (FIValues valsExp al mCols) =
     paren (toSQL valsExp) <-> toSQL al
     <-> toSQL (toColTupExp <$> mCols)
@@ -892,14 +899,20 @@ instance ToSQL CTE where
     CTEUpdate q -> toSQL q
     CTEDelete q -> toSQL q
 
-data SelectWith
+data SelectWithG v
   = SelectWith
-  { swCTEs   :: [(Alias, CTE)]
+  { swCTEs   :: ![(Alias, v)]
   , swSelect :: !Select
-  } deriving (Show, Eq)
+  } deriving (Show, Eq, Generic, Data)
+
+instance (NFData v) => NFData (SelectWithG v)
+instance (Cacheable v) => Cacheable (SelectWithG v)
+instance (Hashable v) => Hashable (SelectWithG v)
 
-instance ToSQL SelectWith where
+instance (ToSQL v) => ToSQL (SelectWithG v) where
   toSQL (SelectWith ctes sel) =
     "WITH " <> (", " <+> map f ctes) <-> toSQL sel
     where
       f (Alias al, q) = toSQL al <-> "AS" <-> paren (toSQL q)
+
+type SelectWith = SelectWithG CTE
diff --git a/server/src-lib/Hasura/SQL/Rewrite.hs b/server/src-lib/Hasura/SQL/Rewrite.hs
index 6235709b1ea18..d7ced56ecc58d 100644
--- a/server/src-lib/Hasura/SQL/Rewrite.hs
+++ b/server/src-lib/Hasura/SQL/Rewrite.hs
@@ -1,5 +1,6 @@
 module Hasura.SQL.Rewrite
   ( prefixNumToAliases
+  , prefixNumToAliasesSelectWith
   ) where
 
 import qualified Data.HashMap.Strict as Map
@@ -20,6 +21,11 @@ prefixNumToAliases :: S.Select -> S.Select
 prefixNumToAliases s =
   uSelect s `evalState` UniqSt 0 Map.empty
 
+prefixNumToAliasesSelectWith
+  :: S.SelectWithG S.Select -> S.SelectWithG S.Select
+prefixNumToAliasesSelectWith s =
+  uSelectWith s `evalState` UniqSt 0 Map.empty
+
 type Rewrite a = State a
 
 data UniqSt
@@ -56,6 +62,12 @@ restoringIdens action = do
   modify' $ \s -> s { _uqIdens = idens }
   return res
 
+uSelectWith :: S.SelectWithG S.Select -> Uniq (S.SelectWithG S.Select)
+uSelectWith (S.SelectWith ctes baseSelect) =
+  S.SelectWith
+    <$> forM ctes (\(als, sel) -> (als,) <$> restoringIdens (uSelect sel))
+    <*> uSelect baseSelect
+
 uSelect :: S.Select -> Uniq S.Select
 uSelect sel = do
   -- this has to be the first thing to process
@@ -113,6 +125,10 @@ uFromItem fromItem = case fromItem of
     newSel <- restoringIdens $ uSelect sel
     newAls <- addAlias al
     return $ S.FISelect isLateral newSel newAls
+  S.FISelectWith isLateral selectWith al -> do
+    newSelectWith <- uSelectWith selectWith
+    newAls <- addAlias al
+    return $ S.FISelectWith isLateral newSelectWith newAls
   S.FIValues (S.ValuesExp tups) als mCols -> do
     newValExp <- fmap S.ValuesExp $
                  forM tups $ \(S.TupleExp ts) ->
@@ -196,8 +212,10 @@ uSqlExp = restoringIdens . \case
     S.SEExcluded <$> return t
   S.SEArray l                   ->
     S.SEArray <$> mapM uSqlExp l
+  S.SEArrayIndex arrayExp indexExp ->
+    S.SEArrayIndex <$> uSqlExp arrayExp <*> uSqlExp indexExp
   S.SETuple (S.TupleExp l)      ->
-    S.SEArray <$> mapM uSqlExp l
+    S.SETuple . S.TupleExp <$> mapM uSqlExp l
   S.SECount cty                 -> return $ S.SECount cty
   S.SENamedArg arg val          -> S.SENamedArg arg <$> uSqlExp val
   S.SEFunction funcExp          -> S.SEFunction <$> uFunctionExp funcExp
diff --git a/server/src-lib/Hasura/Server/Utils.hs b/server/src-lib/Hasura/Server/Utils.hs
index 72d55e55c1aa9..00a079b8efbfc 100644
--- a/server/src-lib/Hasura/Server/Utils.hs
+++ b/server/src-lib/Hasura/Server/Utils.hs
@@ -5,6 +5,7 @@ import           Hasura.Prelude
 
 import           Control.Lens               ((^..))
 import           Data.Aeson
+import           Data.Aeson.Internal
 import           Data.Char
 import           Data.List                  (find)
 import           Language.Haskell.TH.Syntax (Lift, Q, TExp)
@@ -20,6 +21,7 @@ import qualified Data.Text                  as T
 import qualified Data.Text.IO               as TI
 import qualified Data.UUID                  as UUID
 import qualified Data.UUID.V4               as UUID
+import qualified Data.Vector                as V
 import qualified Language.Haskell.TH.Syntax as TH
 import qualified Network.HTTP.Client        as HC
 import qualified Network.HTTP.Types         as HTTP
@@ -227,3 +229,16 @@ makeReasonMessage errors showError =
     [singleError] -> "because " <> showError singleError
     _ -> "for the following reasons:\n" <> T.unlines
          (map (("  • " <>) . showError) errors)
+
+executeJSONPath :: JSONPath -> Value -> IResult Value
+executeJSONPath jsonPath = iparse (valueParser jsonPath)
+  where
+    valueParser path value = case path of
+      []                      -> pure value
+      (pathElement:remaining) -> parseWithPathElement pathElement value >>=
+                                 ((<?> pathElement) . valueParser remaining)
+      where
+        parseWithPathElement = \case
+                  Key k   -> withObject "Object" (.: k)
+                  Index i -> withArray "Array" $
+                             maybe (fail "Array index out of range") pure . (V.!? i)

From b3dd4fd26b9616bbcc47b8eea269c923703c2672 Mon Sep 17 00:00:00 2001
From: rakeshkky <12475069+rakeshkky@users.noreply.github.com>
Date: Mon, 18 May 2020 20:45:24 +0530
Subject: [PATCH 09/29] '/v1/relay' endpoint for relay schema

---
 server/graphql-engine.cabal                   |   1 +
 server/src-lib/Hasura/GraphQL/Execute.hs      |  24 +-
 server/src-lib/Hasura/GraphQL/Explain.hs      |  10 +-
 server/src-lib/Hasura/GraphQL/RelaySchema.hs  | 280 ++++++++++++++++++
 server/src-lib/Hasura/GraphQL/Schema.hs       |  58 +---
 .../src-lib/Hasura/GraphQL/Schema/Common.hs   |  20 +-
 .../src-lib/Hasura/GraphQL/Schema/Function.hs |  12 +
 .../src-lib/Hasura/GraphQL/Schema/Select.hs   |  20 +-
 .../src-lib/Hasura/GraphQL/Transport/HTTP.hs  |  12 +-
 .../Hasura/GraphQL/Transport/WebSocket.hs     |  21 +-
 server/src-lib/Hasura/RQL/DDL/Schema/Cache.hs |   5 +
 .../src-lib/Hasura/RQL/Types/SchemaCache.hs   |   1 +
 server/src-lib/Hasura/Server/App.hs           |  21 +-
 13 files changed, 398 insertions(+), 87 deletions(-)
 create mode 100644 server/src-lib/Hasura/GraphQL/RelaySchema.hs

diff --git a/server/graphql-engine.cabal b/server/graphql-engine.cabal
index 94a735796ca1a..897d00b150794 100644
--- a/server/graphql-engine.cabal
+++ b/server/graphql-engine.cabal
@@ -335,6 +335,7 @@ library
                      , Hasura.GraphQL.Schema.Mutation.Update
                      , Hasura.GraphQL.Schema.Mutation.Delete
                      , Hasura.GraphQL.Schema
+                     , Hasura.GraphQL.RelaySchema
                      , Hasura.GraphQL.Utils
                      , Hasura.GraphQL.Validate
                      , Hasura.GraphQL.Validate.Types
diff --git a/server/src-lib/Hasura/GraphQL/Execute.hs b/server/src-lib/Hasura/GraphQL/Execute.hs
index d5c613e297837..81b8eec891d40 100644
--- a/server/src-lib/Hasura/GraphQL/Execute.hs
+++ b/server/src-lib/Hasura/GraphQL/Execute.hs
@@ -1,5 +1,6 @@
 module Hasura.GraphQL.Execute
   ( GQExecPlan(..)
+  , GraphQLAPIType(..)
 
   , ExecPlanPartial
   , getExecPlanPartial
@@ -39,7 +40,6 @@ import           Hasura.EncJSON
 import           Hasura.GraphQL.Context
 import           Hasura.GraphQL.Logging
 import           Hasura.GraphQL.Resolve.Context
-import           Hasura.GraphQL.Schema
 import           Hasura.GraphQL.Transport.HTTP.Protocol
 import           Hasura.GraphQL.Validate.Types
 import           Hasura.HTTP
@@ -51,6 +51,7 @@ import           Hasura.Server.Utils                    (RequestId, mkClientHead
                                                          mkSetCookieHeaders)
 import           Hasura.Server.Version                  (HasVersion)
 
+import qualified Hasura.GraphQL.Context                 as GC
 import qualified Hasura.GraphQL.Execute.LiveQuery       as EL
 import qualified Hasura.GraphQL.Execute.Plan            as EP
 import qualified Hasura.GraphQL.Execute.Query           as EQ
@@ -60,6 +61,12 @@ import qualified Hasura.GraphQL.Validate.Types          as VT
 import qualified Hasura.Logging                         as L
 import qualified Hasura.Server.Telemetry.Counters       as Telem
 
+-- The GraphQL API type
+data GraphQLAPIType
+  = GATGeneral
+  | GATRelay
+  deriving (Show, Eq)
+
 -- The current execution plan of a graphql operation, it is
 -- currently, either local pg execution or a remote execution
 --
@@ -123,15 +130,19 @@ getExecPlanPartial
   :: (MonadReusability m, MonadError QErr m)
   => UserInfo
   -> SchemaCache
+  -> GraphQLAPIType
   -> Bool
   -> GQLReqParsed
   -> m ExecPlanPartial
-getExecPlanPartial userInfo sc enableAL req = do
+getExecPlanPartial userInfo sc apiType enableAL req = do
 
   -- check if query is in allowlist
   when enableAL checkQueryInAllowlist
 
-  gCtx <- flip runCacheRT sc $ getGCtx role gCtxRoleMap
+  let gCtx = case apiType of
+        GATGeneral -> Map.lookupDefault defaultRemoteGCtx role gCtxRoleMap
+        GATRelay   -> Map.lookupDefault GC.emptyGCtx role relayGCtxMap
+
   queryParts <- flip runReaderT gCtx $ VQ.getQueryParts req
 
   let opDef = VQ.qpOpDef queryParts
@@ -153,6 +164,8 @@ getExecPlanPartial userInfo sc enableAL req = do
   where
     role = userRole userInfo
     gCtxRoleMap = scGCtxMap sc
+    defaultRemoteGCtx = scDefaultRemoteGCtx sc
+    relayGCtxMap = scRelayGCtxMap sc
 
     checkQueryInAllowlist =
       -- only for non-admin roles
@@ -186,12 +199,13 @@ getResolvedExecPlan
   -> Bool
   -> SchemaCache
   -> SchemaCacheVer
+  -> GraphQLAPIType
   -> HTTP.Manager
   -> [N.Header]
   -> GQLReqUnparsed
   -> m (Telem.CacheHit, ExecPlanResolved)
 getResolvedExecPlan pgExecCtx planCache userInfo sqlGenCtx
-  enableAL sc scVer httpManager reqHeaders reqUnparsed = do
+  enableAL sc scVer apiType httpManager reqHeaders reqUnparsed = do
   planM <- liftIO $ EP.getPlan scVer (userRole userInfo)
            opNameM queryStr planCache
   let usrVars = userVars userInfo
@@ -212,7 +226,7 @@ getResolvedExecPlan pgExecCtx planCache userInfo sqlGenCtx
     noExistingPlan = do
       req <- toParsed reqUnparsed
       (partialExecPlan, queryReusability) <- runReusabilityT $
-        getExecPlanPartial userInfo sc enableAL req
+        getExecPlanPartial userInfo sc apiType enableAL req
       forM partialExecPlan $ \(gCtx, rootSelSet) ->
         case rootSelSet of
           VQ.RMutation selSet -> do
diff --git a/server/src-lib/Hasura/GraphQL/Explain.hs b/server/src-lib/Hasura/GraphQL/Explain.hs
index 991665ffbcef9..4f5df3c571d0e 100644
--- a/server/src-lib/Hasura/GraphQL/Explain.hs
+++ b/server/src-lib/Hasura/GraphQL/Explain.hs
@@ -28,8 +28,9 @@ import qualified Hasura.SQL.DML                         as S
 
 data GQLExplain
   = GQLExplain
-  { _gqeQuery :: !GH.GQLReqParsed
-  , _gqeUser  :: !(Maybe (Map.HashMap Text Text))
+  { _gqeQuery   :: !GH.GQLReqParsed
+  , _gqeUser    :: !(Maybe (Map.HashMap Text Text))
+  , _gqeIsRelay :: !(Maybe Bool)
   } deriving (Show, Eq)
 
 $(J.deriveJSON (J.aesonDrop 4 J.camelCase){J.omitNothingFields=True}
@@ -114,9 +115,9 @@ explainGQLQuery
   -> Bool
   -> GQLExplain
   -> m EncJSON
-explainGQLQuery pgExecCtx sc sqlGenCtx enableAL (GQLExplain query userVarsRaw) = do
+explainGQLQuery pgExecCtx sc sqlGenCtx enableAL (GQLExplain query userVarsRaw maybeIsRelay) = do
   (execPlan, queryReusability) <- runReusabilityT $
-    E.getExecPlanPartial userInfo sc enableAL query
+    E.getExecPlanPartial userInfo sc apiType enableAL query
   (gCtx, rootSelSet) <- case execPlan of
     E.GExPHasura (gCtx, rootSelSet) ->
       return (gCtx, rootSelSet)
@@ -131,6 +132,7 @@ explainGQLQuery pgExecCtx sc sqlGenCtx enableAL (GQLExplain query userVarsRaw) =
       (plan, _) <- E.getSubsOp pgExecCtx gCtx sqlGenCtx userInfo queryReusability rootField
       runInTx $ encJFromJValue <$> E.explainLiveQueryPlan plan
   where
+    apiType = bool E.GATGeneral E.GATRelay $ fromMaybe False maybeIsRelay
     usrVars = mkUserVars $ maybe [] Map.toList userVarsRaw
     userInfo = mkUserInfo (fromMaybe adminRole $ roleFromVars usrVars) usrVars
     runInTx = liftEither <=< liftIO . runExceptT . runLazyTx pgExecCtx Q.ReadOnly
diff --git a/server/src-lib/Hasura/GraphQL/RelaySchema.hs b/server/src-lib/Hasura/GraphQL/RelaySchema.hs
new file mode 100644
index 0000000000000..5a11dad74f1a8
--- /dev/null
+++ b/server/src-lib/Hasura/GraphQL/RelaySchema.hs
@@ -0,0 +1,280 @@
+module Hasura.GraphQL.RelaySchema where
+
+import           Control.Lens.Extended          hiding (op)
+
+import qualified Data.HashMap.Strict            as Map
+import qualified Data.HashSet                   as Set
+
+import qualified Data.Text                      as T
+
+import           Hasura.GraphQL.Context
+import           Hasura.GraphQL.Resolve.Types
+import           Hasura.GraphQL.Validate.Types
+import           Hasura.Prelude
+import           Hasura.RQL.Types
+import           Hasura.Server.Utils            (duplicates)
+import           Hasura.SQL.Types
+
+import           Hasura.GraphQL.Schema
+import           Hasura.GraphQL.Schema.BoolExp
+import           Hasura.GraphQL.Schema.Builder
+import           Hasura.GraphQL.Schema.Common
+import           Hasura.GraphQL.Schema.Function
+import           Hasura.GraphQL.Schema.OrderBy
+import           Hasura.GraphQL.Schema.Select
+
+mkRelayGCtxMap
+  :: forall m. (MonadError QErr m)
+  => TableCache -> FunctionCache -> m GCtxMap
+mkRelayGCtxMap tableCache functionCache = do
+  typesMapL <- mapM (mkRelayGCtxMapTable tableCache functionCache) $
+               filter (tableFltr . _tiCoreInfo) $ Map.elems tableCache
+  typesMap <- combineTypes typesMapL
+  let gCtxMap  = flip Map.map typesMap $
+                 \(ty, flds) -> mkGCtx ty flds mempty
+  return gCtxMap
+  where
+    tableFltr ti = not (isSystemDefined $ _tciSystemDefined ti) && isValidObjectName (_tciName ti)
+
+    combineTypes
+      :: [Map.HashMap RoleName (TyAgg, RootFields)]
+      -> m (Map.HashMap RoleName (TyAgg, RootFields))
+    combineTypes maps = do
+      let listMap = foldr (Map.unionWith (++) . Map.map pure) mempty maps
+      flip Map.traverseWithKey listMap $ \_ typeList -> do
+        let tyAgg = mconcat $ map (^. _1) typeList
+        rootFields <- combineRootFields $ map (^. _2) typeList
+        pure (tyAgg, rootFields)
+
+    combineRootFields :: [RootFields] -> m RootFields
+    combineRootFields rootFields = do
+      let duplicateQueryFields = duplicates $
+            concatMap (Map.keys . _rootQueryFields) rootFields
+          duplicateMutationFields = duplicates $
+            concatMap (Map.keys . _rootMutationFields) rootFields
+
+      -- TODO: The following exception should result in inconsistency
+      when (not $ null duplicateQueryFields) $
+        throw400 Unexpected $ "following query root fields are duplicated: "
+        <> showNames duplicateQueryFields
+
+      when (not $ null duplicateMutationFields) $
+        throw400 Unexpected $ "following mutation root fields are duplicated: "
+        <> showNames duplicateMutationFields
+
+      pure $ mconcat rootFields
+
+mkRelayGCtxMapTable
+  :: (MonadError QErr m)
+  => TableCache
+  -> FunctionCache
+  -> TableInfo
+  -> m (Map.HashMap RoleName (TyAgg, RootFields))
+mkRelayGCtxMapTable tableCache funcCache tabInfo = do
+  m <- flip Map.traverseWithKey rolePerms $
+       mkRelayGCtxRole tableCache tn descM fields primaryKey tabFuncs
+  adminSelFlds <- mkAdminSelFlds fields tableCache
+  let adminCtx = mkRelayGCtxRole' tn descM (Just (True, adminSelFlds))
+                 primaryKey tabFuncs
+  return $ Map.insert adminRole (adminCtx, adminRootFlds) m
+  where
+    TableInfo coreInfo rolePerms _ = tabInfo
+    TableCoreInfo tn descM _ fields primaryKey _ _ _ _ _ = coreInfo
+    tabFuncs = filter (isValidObjectName . fiName) $
+               getFuncsOfTable tn funcCache
+    adminRootFlds =
+      getRelayRootFldsRole' tn primaryKey fields tabFuncs
+      (Just (noFilter, Nothing, [], True))
+
+mkRelayGCtxRole
+  :: (MonadError QErr m)
+  => TableCache
+  -> QualifiedTable
+  -> Maybe PGDescription
+  -> FieldInfoMap FieldInfo
+  -> Maybe (PrimaryKey PGColumnInfo)
+  -> [FunctionInfo]
+  -> RoleName
+  -> RolePermInfo
+  -> m (TyAgg, RootFields)
+mkRelayGCtxRole tableCache tn descM fields primaryKey funcs role permInfo = do
+  selPermM <- mapM (getSelPerm tableCache fields role) $ _permSel permInfo
+  let tyAgg = mkRelayGCtxRole' tn descM selPermM primaryKey funcs
+      rootFlds = getRelayRootFldsRole' tn primaryKey fields funcs
+                 (mkSel <$> _permSel permInfo)
+  return (tyAgg, rootFlds)
+  where
+    mkSel s = ( spiFilter s, spiLimit s
+              , spiRequiredHeaders s, spiAllowAgg s
+              )
+
+mkRelayGCtxRole'
+  :: QualifiedTable
+  -> Maybe PGDescription
+  -- ^ Postgres description
+  -> Maybe (Bool, [SelField])
+  -- ^ select permission
+  -> Maybe (PrimaryKey PGColumnInfo)
+  -> [FunctionInfo]
+  -- ^ all functions
+  -> TyAgg
+mkRelayGCtxRole' tn descM selPermM pkeyCols funcs =
+  TyAgg (mkTyInfoMap allTypes) fieldMap scalars ordByCtx
+  where
+    ordByCtx = fromMaybe Map.empty ordByCtxM
+
+    funcInpArgTys = bool [] (map TIInpObj funcArgInpObjs) $ isJust selFldsM
+
+    allTypes = queryTypes <> aggQueryTypes <> funcInpArgTys <> computedFieldFuncArgsInps
+
+    queryTypes = map TIObj selectObjects <>
+      catMaybes
+      [ TIInpObj <$> boolExpInpObjM
+      , TIInpObj <$> ordByInpObjM
+      , TIEnum <$> selColInpTyM
+      ]
+    aggQueryTypes = map TIObj aggObjs <> map TIInpObj aggOrdByInps
+
+    fieldMap = Map.unions $ catMaybes [boolExpInpObjFldsM, selObjFldsM]
+    scalars = selByPkScalarSet <> funcArgScalarSet <> computedFieldFuncArgScalars
+
+    selFldsM = snd <$> selPermM
+    selColNamesM = (map pgiName . getPGColumnFields) <$> selFldsM
+    selColInpTyM = mkSelColumnTy tn <$> selColNamesM
+    -- boolexp input type
+    boolExpInpObjM = (mkBoolExpInp tn) <$> selFldsM
+    -- funcargs input type
+    funcArgInpObjs = flip mapMaybe funcs $ \func ->
+      mkFuncArgsInp (fiName func) (getInputArgs func)
+    -- funcArgCtx = Map.unions funcArgCtxs
+    funcArgScalarSet = funcs ^.. folded.to getInputArgs.folded.to (_qptName.faType)
+
+    -- helper
+    mkFldMap ty = Map.fromList . concatMap (mkFld ty)
+    mkFld ty = \case
+      SFPGColumn ci -> [((ty, pgiName ci), RFPGColumn ci)]
+      SFRelationship (RelationshipFieldInfo relInfo allowAgg cols permFilter permLimit maybePkCols _) ->
+        let relationshipName = riName relInfo
+            relFld = ( (ty, mkRelName relationshipName)
+                     , RFRelationship $ RelationshipField relInfo RFKSimple cols permFilter permLimit
+                     )
+            aggRelFld = ( (ty, mkAggRelName relationshipName)
+                        , RFRelationship $ RelationshipField relInfo RFKAggregate cols permFilter permLimit
+                        )
+            maybeConnFld = maybePkCols <&> \pkCols ->
+                           ( (ty, mkConnectionRelName relationshipName)
+                           , RFRelationship $ RelationshipField relInfo
+                             (RFKConnection pkCols) cols permFilter permLimit
+                           )
+        in case riType relInfo of
+          ObjRel -> [relFld]
+          ArrRel -> bool [relFld] ([relFld, aggRelFld] <> maybe [] pure maybeConnFld) allowAgg
+      SFComputedField cf -> pure
+        ( (ty, mkComputedFieldName $ _cfName cf)
+        , RFComputedField cf
+        )
+
+    -- the fields used in bool exp
+    boolExpInpObjFldsM = mkFldMap (mkBoolExpTy tn) <$> selFldsM
+
+    -- table obj
+    selectObjects = case selPermM of
+      Just (_, selFlds) ->
+        [ mkTableObj tn True descM selFlds
+        , mkTableEdgeObj tn
+        , mkTableConnectionObj tn
+        ]
+      Nothing -> []
+
+    -- aggregate objs and order by inputs
+    (aggObjs, aggOrdByInps) = case selPermM of
+      Just (True, selFlds) ->
+        let cols = getPGColumnFields selFlds
+            numCols = onlyNumCols cols
+            compCols = onlyComparableCols cols
+            objs = [ mkTableAggObj tn
+                   , mkTableAggregateFieldsObj tn (numCols, numAggregateOps) (compCols, compAggregateOps)
+                   ] <> mkColAggregateFieldsObjs selFlds
+            ordByInps = mkTabAggOrdByInpObj tn (numCols, numAggregateOps) (compCols, compAggregateOps)
+                        : mkTabAggregateOpOrdByInpObjs tn (numCols, numAggregateOps) (compCols, compAggregateOps)
+        in (objs, ordByInps)
+      _ -> ([], [])
+
+    getNumericCols = onlyNumCols . getPGColumnFields
+    getComparableCols = onlyComparableCols . getPGColumnFields
+    onlyFloat = const $ mkScalarTy PGFloat
+
+    mkTypeMaker "sum" = mkColumnType
+    mkTypeMaker _     = onlyFloat
+
+    mkColAggregateFieldsObjs flds =
+      let numCols = getNumericCols flds
+          compCols = getComparableCols flds
+          mkNumObjFld n = mkTableColAggregateFieldsObj tn n (mkTypeMaker n) numCols
+          mkCompObjFld n = mkTableColAggregateFieldsObj tn n mkColumnType compCols
+          numFldsObjs = bool (map mkNumObjFld numAggregateOps) [] $ null numCols
+          compFldsObjs = bool (map mkCompObjFld compAggregateOps) [] $ null compCols
+      in numFldsObjs <> compFldsObjs
+    -- the fields used in table object
+    selObjFldsM = mkFldMap (mkTableTy tn) <$> selFldsM
+    -- the scalar set for table_by_pk arguments
+    selByPkScalarSet = pkeyCols ^.. folded.to _pkColumns.folded.to pgiType._PGColumnScalar
+
+    ordByInpCtxM = mkOrdByInpObj tn <$> selFldsM
+    (ordByInpObjM, ordByCtxM) = case ordByInpCtxM of
+      Just (a, b) -> (Just a, Just b)
+      Nothing     -> (Nothing, Nothing)
+
+    -- computed fields' function args input objects and scalar types
+    mkComputedFieldRequiredTypes computedFieldInfo =
+      let ComputedFieldFunction qf inputArgs _ _ = _cfFunction computedFieldInfo
+          scalarArgs = map (_qptName . faType) $ toList inputArgs
+      in (, scalarArgs) <$> mkFuncArgsInp qf inputArgs
+
+    computedFieldReqTypes = catMaybes $
+      maybe [] (map mkComputedFieldRequiredTypes . getComputedFields) selFldsM
+
+    computedFieldFuncArgsInps = map (TIInpObj . fst) computedFieldReqTypes
+    computedFieldFuncArgScalars = Set.fromList $ concatMap snd computedFieldReqTypes
+
+getRelayRootFldsRole'
+  :: QualifiedTable
+  -> Maybe (PrimaryKey PGColumnInfo)
+  -> FieldInfoMap FieldInfo
+  -> [FunctionInfo]
+  -> Maybe (AnnBoolExpPartialSQL, Maybe Int, [T.Text], Bool) -- select filter
+  -> RootFields
+getRelayRootFldsRole' tn primaryKey fields funcs selM =
+  RootFields
+    { _rootQueryFields = makeFieldMap $
+        funcConnectionQueries
+        <> catMaybes
+          [ getSelConnectionDet <$> selM <*> maybePrimaryKeyColumns
+          ]
+    , _rootMutationFields = mempty
+    }
+  where
+    maybePrimaryKeyColumns = fmap _pkColumns primaryKey
+    makeFieldMap = mapFromL (_fiName . snd)
+    colGNameMap = mkPGColGNameMap $ getCols fields
+
+    funcConnectionQueries = fromMaybe [] $ getFuncQueryConnectionFlds
+                            <$> selM <*> maybePrimaryKeyColumns
+
+    getSelConnectionDet (selFltr, pLimit, hdrs, _) primaryKeyColumns =
+      selFldHelper (QCSelectConnection primaryKeyColumns)
+      (mkSelFldConnection Nothing) selFltr pLimit hdrs
+
+    selFldHelper f g pFltr pLimit hdrs =
+      ( f $ SelOpCtx tn hdrs colGNameMap pFltr pLimit
+      , g tn
+      )
+
+    getFuncQueryConnectionFlds (selFltr, pLimit, hdrs, _) primaryKeyColumns =
+      funcFldHelper (QCFuncConnection primaryKeyColumns) mkFuncQueryConnectionFld selFltr pLimit hdrs
+
+    funcFldHelper f g pFltr pLimit hdrs =
+      flip map funcs $ \fi ->
+      ( f $ FuncQOpCtx (fiName fi) (mkFuncArgItemSeq fi) hdrs colGNameMap pFltr pLimit
+      , g fi $ fiDescription fi
+      )
diff --git a/server/src-lib/Hasura/GraphQL/Schema.hs b/server/src-lib/Hasura/GraphQL/Schema.hs
index 46420c6573d53..81594a92a8f40 100644
--- a/server/src-lib/Hasura/GraphQL/Schema.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema.hs
@@ -1,7 +1,7 @@
 module Hasura.GraphQL.Schema
   ( mkGCtxMap
+  , mkGCtx
   , GCtxMap
-  , getGCtx
   , GCtx(..)
   , QueryCtx(..)
   , MutationCtx(..)
@@ -11,6 +11,10 @@ module Hasura.GraphQL.Schema
   , isAggregateField
   , qualObjectToName
   , ppGCtx
+  , getSelPerm
+  , isValidObjectName
+  , mkAdminSelFlds
+  , noFilter
 
   , checkConflictingNode
   , checkSchemaConflicts
@@ -96,18 +100,6 @@ isRelNullable fim ri = isNullable
     lColInfos = getColInfos lCols allCols
     isNullable = any pgiIsNullable lColInfos
 
-mkPGColGNameMap :: [PGColumnInfo] -> PGColGNameMap
-mkPGColGNameMap cols = Map.fromList $
-  flip map cols $ \ci -> (pgiName ci, ci)
-
-numAggregateOps :: [G.Name]
-numAggregateOps = [ "sum", "avg", "stddev", "stddev_samp", "stddev_pop"
-            , "variance", "var_samp", "var_pop"
-            ]
-
-compAggregateOps :: [G.Name]
-compAggregateOps = ["max", "min"]
-
 isAggregateField :: G.Name -> Bool
 isAggregateField = flip elem (numAggregateOps <> compAggregateOps)
 
@@ -225,7 +217,7 @@ mkGCtxRole' tn descM insPermM selPermM updColsM delPermM pkeyCols constraints vi
     mkFldMap ty = Map.fromList . concatMap (mkFld ty)
     mkFld ty = \case
       SFPGColumn ci -> [((ty, pgiName ci), RFPGColumn ci)]
-      SFRelationship (RelationshipFieldInfo relInfo allowAgg cols permFilter permLimit maybePkCols _) ->
+      SFRelationship (RelationshipFieldInfo relInfo allowAgg cols permFilter permLimit _ _) ->
         let relationshipName = riName relInfo
             relFld = ( (ty, mkRelName relationshipName)
                      , RFRelationship $ RelationshipField relInfo RFKSimple cols permFilter permLimit
@@ -233,14 +225,9 @@ mkGCtxRole' tn descM insPermM selPermM updColsM delPermM pkeyCols constraints vi
             aggRelFld = ( (ty, mkAggRelName relationshipName)
                         , RFRelationship $ RelationshipField relInfo RFKAggregate cols permFilter permLimit
                         )
-            maybeConnFld = maybePkCols <&> \pkCols ->
-                           ( (ty, mkConnectionRelName relationshipName)
-                           , RFRelationship $ RelationshipField relInfo
-                             (RFKConnection pkCols) cols permFilter permLimit
-                           )
         in case riType relInfo of
           ObjRel -> [relFld]
-          ArrRel -> bool [relFld] ([relFld, aggRelFld] <> maybe [] pure maybeConnFld) allowAgg
+          ArrRel -> bool [relFld] [relFld, aggRelFld] allowAgg
       SFComputedField cf -> pure
         ( (ty, mkComputedFieldName $ _cfName cf)
         , RFComputedField cf
@@ -261,9 +248,7 @@ mkGCtxRole' tn descM insPermM selPermM updColsM delPermM pkeyCols constraints vi
     -- table obj
     selectObjects = case selPermM of
       Just (_, selFlds) ->
-        [ mkTableObj tn descM selFlds
-        , mkTableEdgeObj tn
-        , mkTableConnectionObj tn
+        [ mkTableObj tn False descM selFlds
         ]
       Nothing -> []
 
@@ -350,11 +335,9 @@ getRootFldsRole' tn primaryKey constraints fields funcs insM
   RootFields
     { _rootQueryFields = makeFieldMap $
         funcQueries
-        <> funcConnectionQueries
         <> funcAggQueries
         <> catMaybes
           [ getSelDet <$> selM
-          , getSelConnectionDet <$> selM <*> maybePrimaryKeyColumns
           , getSelAggDet selM
           , getPKeySelDet <$> selM <*> primaryKey
           ]
@@ -368,14 +351,11 @@ getRootFldsRole' tn primaryKey constraints fields funcs insM
         ]
     }
   where
-    maybePrimaryKeyColumns = fmap _pkColumns primaryKey
     makeFieldMap = mapFromL (_fiName . snd)
     customRootFields = _tcCustomRootFields tableConfig
     colGNameMap = mkPGColGNameMap $ getCols fields
 
     funcQueries = maybe [] getFuncQueryFlds selM
-    funcConnectionQueries = fromMaybe [] $ getFuncQueryConnectionFlds
-                            <$> selM <*> maybePrimaryKeyColumns
     funcAggQueries = maybe [] getFuncAggQueryFlds selM
 
     mutHelper :: (ViewInfo -> Bool) -> (a -> b) -> Maybe a -> Maybe b
@@ -427,9 +407,6 @@ getRootFldsRole' tn primaryKey constraints fields funcs insM
     selCustName = getCustomNameWith _tcrfSelect
     getSelDet (selFltr, pLimit, hdrs, _) =
       selFldHelper QCSelect (mkSelFld selCustName) selFltr pLimit hdrs
-    getSelConnectionDet (selFltr, pLimit, hdrs, _) primaryKeyColumns =
-      selFldHelper (QCSelectConnection primaryKeyColumns)
-      (mkSelFldConnection Nothing) selFltr pLimit hdrs
 
     selAggCustName = getCustomNameWith _tcrfSelectAggregate
     getSelAggDet (Just (selFltr, pLimit, hdrs, True)) =
@@ -452,9 +429,6 @@ getRootFldsRole' tn primaryKey constraints fields funcs insM
     getFuncQueryFlds (selFltr, pLimit, hdrs, _) =
       funcFldHelper QCFuncQuery mkFuncQueryFld selFltr pLimit hdrs
 
-    getFuncQueryConnectionFlds (selFltr, pLimit, hdrs, _) primaryKeyColumns =
-      funcFldHelper (QCFuncConnection primaryKeyColumns) mkFuncQueryConnectionFld selFltr pLimit hdrs
-
     getFuncAggQueryFlds (selFltr, pLimit, hdrs, True) =
       funcFldHelper QCFuncAggQuery mkFuncAggQueryFld selFltr pLimit hdrs
     getFuncAggQueryFlds _                             = []
@@ -465,17 +439,6 @@ getRootFldsRole' tn primaryKey constraints fields funcs insM
       , g fi $ fiDescription fi
       )
 
-    mkFuncArgItemSeq functionInfo =
-      let inputArgs = fiInputArgs functionInfo
-      in Seq.fromList $ procFuncArgs inputArgs nameFn resultFn
-      where
-        nameFn = \case
-          IAUserProvided fa       -> faName fa
-          IASessionVariables name -> Just name
-        resultFn arg gName = flip fmap arg $
-          \fa -> FunctionArgItem (G.Name gName) (faName fa) (faHasDefault fa)
-
-
 getSelPermission :: TableInfo -> RoleName -> Maybe SelPermInfo
 getSelPermission tabInfo role =
   Map.lookup role (_tiRolePermInfoMap tabInfo) >>= _permSel
@@ -789,11 +752,6 @@ mkGCtxMap annotatedObjects tableCache functionCache actionCache = do
 
       pure $ mconcat rootFields
 
-getGCtx :: (CacheRM m) => RoleName -> GCtxMap -> m GCtx
-getGCtx rn ctxMap = do
-  sc <- askSchemaCache
-  return $ fromMaybe (scDefaultRemoteGCtx sc) $ Map.lookup rn ctxMap
-
 -- pretty print GCtx
 ppGCtx :: GCtx -> String
 ppGCtx gCtx =
diff --git a/server/src-lib/Hasura/GraphQL/Schema/Common.hs b/server/src-lib/Hasura/GraphQL/Schema/Common.hs
index c46f327258256..98071bf89e4e0 100644
--- a/server/src-lib/Hasura/GraphQL/Schema/Common.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/Common.hs
@@ -27,6 +27,11 @@ module Hasura.GraphQL.Schema.Common
   , mkDescriptionWith
 
   , mkFuncArgsTy
+
+  , mkPGColGNameMap
+
+  , numAggregateOps
+  , compAggregateOps
   ) where
 
 import qualified Data.HashMap.Strict           as Map
@@ -73,7 +78,8 @@ qualObjectToName :: (ToTxt a) => QualifiedObject a -> G.Name
 qualObjectToName = G.Name . snakeCaseQualObject
 
 addTypeSuffix :: Text -> G.NamedType -> G.NamedType
-addTypeSuffix suffix baseType = G.NamedType $ G.unNamedType baseType <> G.Name suffix
+addTypeSuffix suffix baseType =
+  G.NamedType $ G.unNamedType baseType <> G.Name suffix
 
 fromInpValL :: [InpValInfo] -> Map.HashMap G.Name InpValInfo
 fromInpValL = mapFromL _iviName
@@ -135,3 +141,15 @@ mkFuncArgsName fn =
 mkFuncArgsTy :: QualifiedFunction -> G.NamedType
 mkFuncArgsTy =
   G.NamedType . mkFuncArgsName
+
+mkPGColGNameMap :: [PGColumnInfo] -> PGColGNameMap
+mkPGColGNameMap cols = Map.fromList $
+  flip map cols $ \ci -> (pgiName ci, ci)
+
+numAggregateOps :: [G.Name]
+numAggregateOps = [ "sum", "avg", "stddev", "stddev_samp", "stddev_pop"
+            , "variance", "var_samp", "var_pop"
+            ]
+
+compAggregateOps :: [G.Name]
+compAggregateOps = ["max", "min"]
diff --git a/server/src-lib/Hasura/GraphQL/Schema/Function.hs b/server/src-lib/Hasura/GraphQL/Schema/Function.hs
index 79b4212eb509b..426fe22a08f90 100644
--- a/server/src-lib/Hasura/GraphQL/Schema/Function.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/Function.hs
@@ -5,12 +5,14 @@ module Hasura.GraphQL.Schema.Function
   , mkFuncQueryConnectionFld
   , mkFuncAggQueryFld
   , mkFuncArgsTy
+  , mkFuncArgItemSeq
   ) where
 
 import qualified Data.Sequence                 as Seq
 import qualified Data.Text                     as T
 import qualified Language.GraphQL.Draft.Syntax as G
 
+import           Hasura.GraphQL.Resolve.Types
 import           Hasura.GraphQL.Schema.Common
 import           Hasura.GraphQL.Schema.Select
 import           Hasura.GraphQL.Validate.Types
@@ -135,3 +137,13 @@ mkFuncAggQueryFld funInfo descM =
     ty = G.toGT $ G.toNT $ mkTableAggTy retTable
 
 
+mkFuncArgItemSeq :: FunctionInfo -> Seq (InputArgument FunctionArgItem)
+mkFuncArgItemSeq functionInfo =
+  let inputArgs = fiInputArgs functionInfo
+  in Seq.fromList $ procFuncArgs inputArgs nameFn resultFn
+  where
+    nameFn = \case
+      IAUserProvided fa       -> faName fa
+      IASessionVariables name -> Just name
+    resultFn arg gName = flip fmap arg $
+      \fa -> FunctionArgItem (G.Name gName) (faName fa) (faHasDefault fa)
diff --git a/server/src-lib/Hasura/GraphQL/Schema/Select.hs b/server/src-lib/Hasura/GraphQL/Schema/Select.hs
index c41d8f7220559..f4a7d63004f51 100644
--- a/server/src-lib/Hasura/GraphQL/Schema/Select.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/Select.hs
@@ -166,11 +166,12 @@ object_relationship: remote_table
 mkRelationshipField
   :: Bool
   -> RelInfo
+  -> Bool
   -> Maybe (NonEmpty PGColumnInfo)
   -> Bool
   -> [ObjFldInfo]
-mkRelationshipField allowAgg (RelInfo rn rTy _ remTab isManual) maybePkCols isNullable = case rTy of
-  ArrRel -> bool [arrRelFld] ([arrRelFld, aggArrRelFld] <> arrConnectionFld) allowAgg
+mkRelationshipField allowAgg (RelInfo rn rTy _ remTab isManual) isRelay maybePkCols isNullable = case rTy of
+  ArrRel -> bool [arrRelFld] ([arrRelFld, aggArrRelFld] <> connFields) allowAgg
   ObjRel -> [objRelFld]
   where
     objRelFld = mkHsraObjFldInfo (Just "An object relationship")
@@ -193,6 +194,8 @@ mkRelationshipField allowAgg (RelInfo rn rTy _ remTab isManual) maybePkCols isNu
       (mkAggRelName rn) (fromInpValL $ mkSelArgs remTab) $
       G.toGT $ G.toNT $ mkTableAggTy remTab
 
+    connFields = bool [] arrConnectionFld isRelay
+
 {-
 type table {
   col1: colty1
@@ -203,10 +206,11 @@ type table {
 -}
 mkTableObj
   :: QualifiedTable
+  -> Bool
   -> Maybe PGDescription
   -> [SelField]
   -> ObjTyInfo
-mkTableObj tn descM allowedFlds =
+mkTableObj tn isRelay descM allowedFlds =
   mkObjTyInfo (Just desc) (mkTableTy tn) Set.empty (mapFromL _fiName flds) TLHasuraType
   where
     flds = pgColumnFields <> relFlds <> computedFlds
@@ -214,7 +218,7 @@ mkTableObj tn descM allowedFlds =
     relFlds = concatMap mkRelationshipField' $ getRelationshipFields allowedFlds
     computedFlds = map mkComputedFieldFld $ getComputedFields allowedFlds
     mkRelationshipField' (RelationshipFieldInfo relInfo allowAgg _ _ _ maybePkCols isNullable) =
-      mkRelationshipField allowAgg relInfo maybePkCols isNullable
+      mkRelationshipField allowAgg relInfo isRelay maybePkCols isNullable
     desc = mkDescriptionWith descM $ "columns and relationships of " <>> tn
 
 {-
@@ -255,7 +259,7 @@ mkTableAggregateFieldsObj
   -> ([PGColumnInfo], [G.Name])
   -> ([PGColumnInfo], [G.Name])
   -> ObjTyInfo
-mkTableAggregateFieldsObj tn (numCols, numAggregateOps) (compCols, compAggregateOps) =
+mkTableAggregateFieldsObj tn (numCols, numericAggregateOps) (compCols, compareAggregateOps) =
   mkHsraObjTyInfo (Just desc) (mkTableAggregateFieldsTy tn) Set.empty $ mapFromL _fiName $
   countFld : (numFlds <> compFlds)
   where
@@ -272,8 +276,8 @@ mkTableAggregateFieldsObj tn (numCols, numAggregateOps) (compCols, compAggregate
     distinctInpVal = InpValInfo Nothing "distinct" Nothing $ G.toGT $
                      mkScalarTy PGBoolean
 
-    numFlds = bool (map mkColumnOpFld numAggregateOps) [] $ null numCols
-    compFlds = bool (map mkColumnOpFld compAggregateOps) [] $ null compCols
+    numFlds = bool (map mkColumnOpFld numericAggregateOps) [] $ null numCols
+    compFlds = bool (map mkColumnOpFld compareAggregateOps) [] $ null compCols
 
     mkColumnOpFld op = mkHsraObjFldInfo Nothing op Map.empty $ G.toGT $
                     mkTableColAggregateFieldsTy op tn
@@ -351,7 +355,7 @@ mkTableConnectionObj tn =
   where
     desc = G.Description $ "A Relay Connection object on " <>> tn
     pageInfoFld = mkHsraObjFldInfo Nothing "pageInfo" Map.empty $
-                  G.toGT $ G.toNT $ pageInfoTy
+                  G.toGT $ G.toNT pageInfoTy
     edgesFld = mkHsraObjFldInfo Nothing "edges" Map.empty $ G.toGT $
                G.toNT $ G.toLT $ G.toNT $ mkTableEdgeTy tn
 
diff --git a/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs b/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs
index 3ee15ccba6a13..3180ddd3cafad 100644
--- a/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs
+++ b/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs
@@ -31,15 +31,16 @@ runGQ
   => RequestId
   -> UserInfo
   -> [N.Header]
+  -> E.GraphQLAPIType
   -> GQLReq GQLQueryText
   -> m (HttpResponse EncJSON)
-runGQ reqId userInfo reqHdrs req = do
+runGQ reqId userInfo reqHdrs apiType req = do
   -- The response and misc telemetry data:
   let telemTransport = Telem.HTTP
   (telemTimeTot_DT, (telemCacheHit, telemLocality, (telemTimeIO_DT, telemQueryType, !resp))) <- withElapsedTime $ do
     E.ExecutionCtx _ sqlGenCtx pgExecCtx planCache sc scVer httpManager enableAL <- ask
     (telemCacheHit, execPlan) <- E.getResolvedExecPlan pgExecCtx planCache
-                userInfo sqlGenCtx enableAL sc scVer httpManager reqHdrs req
+                                 userInfo sqlGenCtx enableAL sc scVer apiType httpManager reqHdrs req
     case execPlan of
       E.GExPHasura resolvedOp -> do
         (telemTimeIO, telemQueryType, respHdrs, resp) <- runHasuraGQ reqId req userInfo resolvedOp
@@ -63,12 +64,13 @@ runGQBatched
   => RequestId
   -> UserInfo
   -> [N.Header]
+  -> E.GraphQLAPIType
   -> GQLBatchedReqs GQLQueryText
   -> m (HttpResponse EncJSON)
-runGQBatched reqId userInfo reqHdrs reqs =
+runGQBatched reqId userInfo reqHdrs apiType reqs =
   case reqs of
     GQLSingleRequest req ->
-      runGQ reqId userInfo reqHdrs req
+      runGQ reqId userInfo reqHdrs apiType req
     GQLBatchedReqs batch -> do
       -- It's unclear what we should do if we receive multiple
       -- responses with distinct headers, so just do the simplest thing
@@ -79,7 +81,7 @@ runGQBatched reqId userInfo reqHdrs reqs =
             . map (either (encJFromJValue . encodeGQErr False) _hrBody)
           try = flip catchError (pure . Left) . fmap Right
       fmap removeHeaders $
-        traverse (try . runGQ reqId userInfo reqHdrs) batch
+        traverse (try . runGQ reqId userInfo reqHdrs apiType) batch
 
 runHasuraGQ
   :: ( MonadIO m
diff --git a/server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs b/server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs
index 3102cd6cc8ebf..8ca2d6edf3385 100644
--- a/server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs
+++ b/server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs
@@ -94,6 +94,7 @@ data WSConnData
   -- are not tracked here
   , _wscOpMap     :: !OperationMap
   , _wscErrRespTy :: !ErrRespType
+  , _wscAPIType   :: !E.GraphQLAPIType
   }
 
 type WSServer = WS.WSServer WSConnData
@@ -203,11 +204,11 @@ onConn :: (MonadIO m)
        => L.Logger L.Hasura -> CorsPolicy -> WS.OnConnH m WSConnData
 onConn (L.Logger logger) corsPolicy wsId requestHead = do
   res <- runExceptT $ do
-    errType <- checkPath
+    (errType, apiType) <- checkPath
     let reqHdrs = WS.requestHeaders requestHead
     headers <- maybe (return reqHdrs) (flip enforceCors reqHdrs . snd) getOrigin
-    return (WsHeaders $ filterWsHeaders headers, errType)
-  either reject (uncurry accept) res
+    return (WsHeaders $ filterWsHeaders headers, errType, apiType)
+  either reject accept res
 
   where
     keepAliveAction wsConn = liftIO $ forever $ do
@@ -225,12 +226,13 @@ onConn (L.Logger logger) corsPolicy wsId requestHead = do
       currTime <- TC.getCurrentTime
       sleep $ fromUnits $ TC.diffUTCTime expTime currTime
 
-    accept hdrs errType = do
+    accept (hdrs, errType, apiType) = do
       logger $ mkWsInfoLog Nothing (WsConnInfo wsId Nothing Nothing) EAccepted
       connData <- liftIO $ WSConnData
                   <$> STM.newTVarIO (CSNotInitialised hdrs)
                   <*> STMMap.newIO
                   <*> pure errType
+                  <*> pure apiType
       let acceptRequest = WS.defaultAcceptRequest
                           { WS.acceptSubprotocol = Just "graphql-ws"}
       return $ Right $ WS.AcceptWith connData acceptRequest keepAliveAction tokenExpiryHandler
@@ -243,8 +245,9 @@ onConn (L.Logger logger) corsPolicy wsId requestHead = do
         (BL.toStrict $ J.encode $ encodeGQLErr False qErr)
 
     checkPath = case WS.requestPath requestHead of
-      "/v1alpha1/graphql" -> return ERTLegacy
-      "/v1/graphql"       -> return ERTGraphqlCompliant
+      "/v1alpha1/graphql" -> return (ERTLegacy, E.GATGeneral)
+      "/v1/graphql"       -> return (ERTGraphqlCompliant, E.GATGeneral)
+      "/v1/relay"         -> return (ERTGraphqlCompliant, E.GATRelay)
       _                   ->
         throw404 "only '/v1/graphql', '/v1alpha1/graphql' are supported on websockets"
 
@@ -306,7 +309,7 @@ onStart serverEnv wsConn (StartMsg opId q) = catchAndIgnore $ do
   requestId <- getRequestId reqHdrs
   (sc, scVer) <- liftIO getSchemaCache
   execPlanE <- runExceptT $ E.getResolvedExecPlan pgExecCtx
-               planCache userInfo sqlGenCtx enableAL sc scVer httpMgr reqHdrs q
+               planCache userInfo sqlGenCtx enableAL sc scVer apiType httpMgr reqHdrs q
 
   (telemCacheHit, execPlan) <- either (withComplete . preExecErr requestId) return execPlanE
   let execCtx = E.ExecutionCtx logger sqlGenCtx pgExecCtx
@@ -397,7 +400,7 @@ onStart serverEnv wsConn (StartMsg opId q) = catchAndIgnore $ do
     WSServerEnv logger pgExecCtx lqMap getSchemaCache httpMgr _ sqlGenCtx planCache
       _ enableAL = serverEnv
 
-    WSConnData userInfoR opMap errRespTy = WS.getData wsConn
+    WSConnData userInfoR opMap errRespTy apiType = WS.getData wsConn
 
     logOpEv opTy reqId =
       logWSEvent logger wsConn $ EOperation opDet
@@ -522,7 +525,7 @@ logWSEvent (L.Logger logger) wsConn wsEv = do
         _                               -> (Nothing, Nothing)
   liftIO $ logger $ WSLog logLevel $ WSLogInfo userVarsM (WsConnInfo wsId tokenExpM Nothing) wsEv
   where
-    WSConnData userInfoR _ _ = WS.getData wsConn
+    WSConnData userInfoR _ _ _ = WS.getData wsConn
     wsId = WS.getWSId wsConn
     logLevel = bool L.LevelInfo L.LevelError isError
     isError = case wsEv of
diff --git a/server/src-lib/Hasura/RQL/DDL/Schema/Cache.hs b/server/src-lib/Hasura/RQL/DDL/Schema/Cache.hs
index ee37fafc15cde..ceb475b2f1cae 100644
--- a/server/src-lib/Hasura/RQL/DDL/Schema/Cache.hs
+++ b/server/src-lib/Hasura/RQL/DDL/Schema/Cache.hs
@@ -32,6 +32,7 @@ import           Data.Aeson
 import           Data.List                                (nub)
 
 import qualified Hasura.GraphQL.Context                   as GC
+import qualified Hasura.GraphQL.RelaySchema               as Relay
 import qualified Hasura.GraphQL.Schema                    as GS
 import qualified Hasura.GraphQL.Validate.Types            as VT
 import qualified Hasura.Incremental                       as Inc
@@ -176,6 +177,9 @@ buildSchemaCacheRule = proc (catalogMetadata, invalidationKeys) -> do
                                     , _boActions resolvedOutputs
                                     )
 
+  -- Step 4: Build the relay GraphQL schema
+  relayGQLSchema <- bindA -< Relay.mkRelayGCtxMap (_boTables resolvedOutputs) (_boFunctions resolvedOutputs)
+
   returnA -< SchemaCache
     { scTables = _boTables resolvedOutputs
     , scActions = _boActions resolvedOutputs
@@ -185,6 +189,7 @@ buildSchemaCacheRule = proc (catalogMetadata, invalidationKeys) -> do
     , scCustomTypes = _boCustomTypes resolvedOutputs
     , scGCtxMap = gqlSchema
     , scDefaultRemoteGCtx = remoteGQLSchema
+    , scRelayGCtxMap = relayGQLSchema
     , scDepMap = resolvedDependencies
     , scInconsistentObjs =
         inconsistentObjects <> dependencyInconsistentObjects <> toList gqlSchemaInconsistentObjects
diff --git a/server/src-lib/Hasura/RQL/Types/SchemaCache.hs b/server/src-lib/Hasura/RQL/Types/SchemaCache.hs
index 9955a8e2ed69f..8e41ad6f50c38 100644
--- a/server/src-lib/Hasura/RQL/Types/SchemaCache.hs
+++ b/server/src-lib/Hasura/RQL/Types/SchemaCache.hs
@@ -198,6 +198,7 @@ data SchemaCache
   , scCustomTypes       :: !(NonObjectTypeMap, AnnotatedObjects)
   , scGCtxMap           :: !GC.GCtxMap
   , scDefaultRemoteGCtx :: !GC.GCtx
+  , scRelayGCtxMap      :: !GC.GCtxMap
   , scDepMap            :: !DepMap
   , scInconsistentObjs  :: ![InconsistentMetadata]
   } deriving (Show, Eq)
diff --git a/server/src-lib/Hasura/Server/App.hs b/server/src-lib/Hasura/Server/App.hs
index fbaa8d953f000..51c8bd7ea9148 100644
--- a/server/src-lib/Hasura/Server/App.hs
+++ b/server/src-lib/Hasura/Server/App.hs
@@ -313,8 +313,10 @@ v1QueryHandler query = do
       instanceId <- scInstanceId . hcServerCtx <$> ask
       runQuery pgExecCtx instanceId userInfo schemaCache httpMgr sqlGenCtx (SystemDefined False) query
 
-v1Alpha1GQHandler :: (HasVersion, MonadIO m) => GH.GQLBatchedReqs GH.GQLQueryText -> Handler m (HttpResponse EncJSON)
-v1Alpha1GQHandler query = do
+v1Alpha1GQHandler
+  :: (HasVersion, MonadIO m)
+  => E.GraphQLAPIType -> GH.GQLBatchedReqs GH.GQLQueryText -> Handler m (HttpResponse EncJSON)
+v1Alpha1GQHandler apiType query = do
   userInfo <- asks hcUser
   reqHeaders <- asks hcReqHeaders
   manager <- scManager . hcServerCtx <$> ask
@@ -328,13 +330,19 @@ v1Alpha1GQHandler query = do
   requestId <- asks hcRequestId
   let execCtx = E.ExecutionCtx logger sqlGenCtx pgExecCtx planCache
                 (lastBuiltSchemaCache sc) scVer manager enableAL
-  flip runReaderT execCtx $ GH.runGQBatched requestId userInfo reqHeaders query
+  flip runReaderT execCtx $ GH.runGQBatched requestId userInfo reqHeaders apiType query
 
 v1GQHandler
   :: (HasVersion, MonadIO m)
   => GH.GQLBatchedReqs GH.GQLQueryText
   -> Handler m (HttpResponse EncJSON)
-v1GQHandler = v1Alpha1GQHandler
+v1GQHandler = v1Alpha1GQHandler E.GATGeneral
+
+v1GQRelayHandler
+  :: (HasVersion, MonadIO m)
+  => GH.GQLBatchedReqs GH.GQLQueryText
+  -> Handler m (HttpResponse EncJSON)
+v1GQRelayHandler = v1Alpha1GQHandler E.GATRelay
 
 gqlExplainHandler :: (MonadIO m) => GE.GQLExplain -> Handler m (HttpResponse EncJSON)
 gqlExplainHandler query = do
@@ -601,11 +609,14 @@ httpApp corsCfg serverCtx enableConsole consoleAssetsDir enableTelemetry = do
 
     when enableGraphQL $ do
       Spock.post "v1alpha1/graphql" $ spockAction GH.encodeGQErr id $
-        mkPostHandler $ mkAPIRespHandler v1Alpha1GQHandler
+        mkPostHandler $ mkAPIRespHandler $ v1Alpha1GQHandler E.GATGeneral
 
       Spock.post "v1/graphql" $ spockAction GH.encodeGQErr allMod200 $
         mkPostHandler $ mkAPIRespHandler v1GQHandler
 
+      Spock.post "v1/relay" $ spockAction GH.encodeGQErr allMod200 $
+        mkPostHandler $ mkAPIRespHandler v1GQRelayHandler
+
     when (isDeveloperAPIEnabled serverCtx) $ do
       Spock.get "dev/ekg" $ spockAction encodeQErr id $
         mkGetHandler $ do

From e797e32e0a141fdce0eb913987bdc7db9c0d3eae Mon Sep 17 00:00:00 2001
From: rakeshkky <12475069+rakeshkky@users.noreply.github.com>
Date: Tue, 26 May 2020 17:14:23 +0530
Subject: [PATCH 10/29] implement 'Node' interface and top level 'node' field
 resolver

---
 server/src-lib/Hasura/GraphQL/Execute.hs      | 39 ++------
 .../Hasura/GraphQL/Execute/LiveQuery/Plan.hs  | 35 +++++---
 server/src-lib/Hasura/GraphQL/Explain.hs      |  6 +-
 server/src-lib/Hasura/GraphQL/NormalForm.hs   | 59 +++++++------
 server/src-lib/Hasura/GraphQL/RelaySchema.hs  | 88 ++++++++++++++++---
 server/src-lib/Hasura/GraphQL/Resolve.hs      | 20 +++--
 .../src-lib/Hasura/GraphQL/Resolve/BoolExp.hs |  2 +
 .../src-lib/Hasura/GraphQL/Resolve/Context.hs | 13 +--
 .../Hasura/GraphQL/Resolve/Introspect.hs      |  4 +-
 .../src-lib/Hasura/GraphQL/Resolve/Select.hs  | 67 ++++++++++++--
 .../src-lib/Hasura/GraphQL/Resolve/Types.hs   | 16 +++-
 server/src-lib/Hasura/GraphQL/Schema.hs       |  2 +-
 .../src-lib/Hasura/GraphQL/Schema/Common.hs   | 11 +++
 .../src-lib/Hasura/GraphQL/Schema/OrderBy.hs  | 12 +--
 .../src-lib/Hasura/GraphQL/Schema/Select.hs   | 26 +++++-
 .../src-lib/Hasura/GraphQL/Transport/HTTP.hs  | 20 ++---
 server/src-lib/Hasura/GraphQL/Validate.hs     | 11 ++-
 .../Hasura/GraphQL/Validate/SelectionSet.hs   | 67 +++++++-------
 .../src-lib/Hasura/GraphQL/Validate/Types.hs  |  4 +-
 server/src-lib/Hasura/Prelude.hs              |  9 ++
 server/src-lib/Hasura/RQL/DML/Select.hs       | 12 +--
 .../src-lib/Hasura/RQL/DML/Select/Internal.hs | 47 +++++++---
 server/src-lib/Hasura/RQL/DML/Select/Types.hs |  2 +
 server/src-lib/Hasura/Server/Utils.hs         |  2 -
 .../basic/select_query_fragment_cycles.yaml   |  2 +-
 server/tests-py/test_schema_stitching.py      |  4 +-
 26 files changed, 388 insertions(+), 192 deletions(-)

diff --git a/server/src-lib/Hasura/GraphQL/Execute.hs b/server/src-lib/Hasura/GraphQL/Execute.hs
index a2738cd6e5d81..8e1bdb9e1644f 100644
--- a/server/src-lib/Hasura/GraphQL/Execute.hs
+++ b/server/src-lib/Hasura/GraphQL/Execute.hs
@@ -236,9 +236,9 @@ getResolvedExecPlan pgExecCtx planCache userInfo sqlGenCtx
               (allowQueryActionExecuter httpManager reqHeaders) selSet
             traverse_ (addPlanToCache . EP.RPQuery) plan
             return $ ExOpQuery queryTx (Just genSql)
-          VQ.RSubscription alias fld -> do
+          VQ.RSubscription fields -> do
             (lqOp, plan) <- getSubsOp pgExecCtx gCtx sqlGenCtx userInfo queryReusability
-              (restrictActionExecuter "query actions cannot be run as a subscription") alias fld
+              (restrictActionExecuter "query actions cannot be run as a subscription") fields
             traverse_ (addPlanToCache . EP.RPSubs) plan
             return $ ExOpSubs lqOp
 
@@ -347,33 +347,6 @@ getMutOp ctx sqlGenCtx userInfo manager reqHeaders selSet =
         ordByCtx = _gOrdByCtx ctx
         insCtxMap = _gInsCtxMap ctx
 
-getSubsOpM
-  :: ( MonadError QErr m
-     , MonadReader r m
-     , Has QueryCtxMap r
-     , Has FieldMap r
-     , Has OrdByCtx r
-     , Has SQLGenCtx r
-     , Has UserInfo r
-     , MonadIO m
-     , HasVersion
-     )
-  => PGExecCtx
-  -> QueryReusability
-  -> G.Alias
-  -> VQ.Field
-  -> QueryActionExecuter
-  -> m (EL.LiveQueryPlan, Maybe EL.ReusableLiveQueryPlan)
-getSubsOpM pgExecCtx initialReusability alias fld actionExecuter =
-  case VQ._fName fld of
-    "__typename" ->
-      throwVE "you cannot create a subscription on '__typename' field"
-    _            -> do
-      (astUnresolved, finalReusability) <- runReusabilityTWith initialReusability $
-        GR.queryFldToPGAST fld actionExecuter
-      let varTypes = finalReusability ^? _Reusable
-      EL.buildLiveQueryPlan pgExecCtx alias astUnresolved varTypes
-
 getSubsOp
   :: ( MonadError QErr m
      , MonadIO m
@@ -385,11 +358,11 @@ getSubsOp
   -> UserInfo
   -> QueryReusability
   -> QueryActionExecuter
-  -> G.Alias
-  -> VQ.Field
+  -> VQ.ObjectSelectionSet
   -> m (EL.LiveQueryPlan, Maybe EL.ReusableLiveQueryPlan)
-getSubsOp pgExecCtx gCtx sqlGenCtx userInfo queryReusability actionExecuter alias fld =
-  runE gCtx sqlGenCtx userInfo $ getSubsOpM pgExecCtx queryReusability alias fld actionExecuter
+getSubsOp pgExecCtx gCtx sqlGenCtx userInfo queryReusability actionExecuter =
+  runE gCtx sqlGenCtx userInfo .
+  EL.buildLiveQueryPlan pgExecCtx queryReusability actionExecuter
 
 execRemoteGQ
   :: ( HasVersion
diff --git a/server/src-lib/Hasura/GraphQL/Execute/LiveQuery/Plan.hs b/server/src-lib/Hasura/GraphQL/Execute/LiveQuery/Plan.hs
index 2ea103244913a..54f8f16cd1dc7 100644
--- a/server/src-lib/Hasura/GraphQL/Execute/LiveQuery/Plan.hs
+++ b/server/src-lib/Hasura/GraphQL/Execute/LiveQuery/Plan.hs
@@ -30,6 +30,7 @@ import qualified Data.Aeson.Casing                      as J
 import qualified Data.Aeson.Extended                    as J
 import qualified Data.Aeson.TH                          as J
 import qualified Data.HashMap.Strict                    as Map
+import qualified Data.HashMap.Strict.InsOrd             as OMap
 import qualified Data.Text                              as T
 import qualified Data.UUID.V4                           as UUID
 import qualified Database.PG.Query                      as Q
@@ -50,6 +51,10 @@ import qualified Hasura.SQL.DML                         as S
 
 import           Hasura.Db
 import           Hasura.EncJSON
+import           Hasura.GraphQL.Resolve.Action
+import           Hasura.GraphQL.Resolve.Types
+import           Hasura.GraphQL.Validate.SelectionSet
+import           Hasura.GraphQL.Validate.Types
 import           Hasura.RQL.Types
 import           Hasura.Server.Version                  (HasVersion)
 import           Hasura.SQL.Error
@@ -62,7 +67,7 @@ import           Hasura.SQL.Value
 newtype MultiplexedQuery = MultiplexedQuery { unMultiplexedQuery :: Q.Query }
   deriving (Show, Eq, Hashable, J.ToJSON)
 
-mkMultiplexedQuery :: Map.HashMap G.Alias GR.QueryRootFldResolved -> MultiplexedQuery
+mkMultiplexedQuery :: OMap.InsOrdHashMap G.Alias GR.QueryRootFldResolved -> MultiplexedQuery
 mkMultiplexedQuery rootFields = MultiplexedQuery . Q.fromBuilder . toSQL $ S.mkSelect
   { S.selExtr =
     -- SELECT _subs.result_id, _fld_resp.root AS result
@@ -83,13 +88,13 @@ mkMultiplexedQuery rootFields = MultiplexedQuery . Q.fromBuilder . toSQL $ S.mkS
     selectRootFields = S.mkSelect
       { S.selExtr = [S.Extractor rootFieldsJsonAggregate (Just . S.Alias $ Iden "root")]
       , S.selFrom = Just . S.FromExp $
-          flip map (Map.toList rootFields) $ \(fieldAlias, resolvedAST) ->
+          flip map (OMap.toList rootFields) $ \(fieldAlias, resolvedAST) ->
             GR.toSQLFromItem (S.Alias $ aliasToIden fieldAlias) resolvedAST
       }
 
     -- json_build_object('field1', field1.root, 'field2', field2.root, ...)
     rootFieldsJsonAggregate = S.SEFnApp "json_build_object" rootFieldsJsonPairs Nothing
-    rootFieldsJsonPairs = flip concatMap (Map.keys rootFields) $ \fieldAlias ->
+    rootFieldsJsonPairs = flip concatMap (OMap.keys rootFields) $ \fieldAlias ->
       [ S.SELit (G.unName $ G.unAlias fieldAlias)
       , mkQualIden (aliasToIden fieldAlias) (Iden "root") ]
 
@@ -264,19 +269,28 @@ buildLiveQueryPlan
   :: ( MonadError QErr m
      , MonadReader r m
      , Has UserInfo r
+     , Has FieldMap r
+     , Has OrdByCtx r
+     , Has QueryCtxMap r
+     , Has SQLGenCtx r
      , MonadIO m
+     , HasVersion
      )
   => PGExecCtx
-  -> G.Alias
-  -> GR.QueryRootFldUnresolved
-  -> Maybe GV.ReusableVariableTypes
+  -> QueryReusability
+  -> QueryActionExecuter
+  -> ObjectSelectionSet
   -> m (LiveQueryPlan, Maybe ReusableLiveQueryPlan)
-buildLiveQueryPlan pgExecCtx alias unresolvedAST varTypes = do
-  (resolvedAST, (queryVariableValues, syntheticVariableValues)) <-
-    flip runStateT mempty $ GR.traverseQueryRootFldAST resolveMultiplexedValue unresolvedAST
+buildLiveQueryPlan pgExecCtx initialReusability actionExecuter selectionSet = do
+  ((resolvedASTMap, (queryVariableValues, syntheticVariableValues)), finalReusability) <-
+    runReusabilityTWith initialReusability $
+      flip runStateT mempty $ flip OMap.traverseWithKey (unAliasedFields $ unObjectSelectionSet selectionSet) $
+      \_ field -> do
+        unresolvedAST <- GR.queryFldToPGAST field actionExecuter
+        GR.traverseQueryRootFldAST resolveMultiplexedValue unresolvedAST
 
   userInfo <- asks getter
-  let multiplexedQuery = mkMultiplexedQuery $ Map.singleton alias resolvedAST
+  let multiplexedQuery = mkMultiplexedQuery resolvedASTMap
       roleName = _uiRole userInfo
       parameterizedPlan = ParameterizedLiveQueryPlan roleName multiplexedQuery
 
@@ -287,6 +301,7 @@ buildLiveQueryPlan pgExecCtx alias unresolvedAST varTypes = do
   validatedSyntheticVars <- validateVariables pgExecCtx (toList syntheticVariableValues)
   let cohortVariables = CohortVariables (_uiSession userInfo) validatedQueryVars validatedSyntheticVars
       plan = LiveQueryPlan parameterizedPlan cohortVariables
+      varTypes = finalReusability ^? _Reusable
       reusablePlan = ReusableLiveQueryPlan parameterizedPlan validatedSyntheticVars <$> varTypes
   pure (plan, reusablePlan)
 
diff --git a/server/src-lib/Hasura/GraphQL/Explain.hs b/server/src-lib/Hasura/GraphQL/Explain.hs
index fb79021339ee2..81508ce94ca19 100644
--- a/server/src-lib/Hasura/GraphQL/Explain.hs
+++ b/server/src-lib/Hasura/GraphQL/Explain.hs
@@ -131,16 +131,16 @@ explainGQLQuery pgExecCtx sc sqlGenCtx enableAL actionExecuter (GQLExplain query
   (gCtx, rootSelSet) <- case execPlan of
     E.GExPHasura (gCtx, rootSelSet) ->
       return (gCtx, rootSelSet)
-    E.GExPRemote _ _ _  ->
+    E.GExPRemote{}  ->
       throw400 InvalidParams "only hasura queries can be explained"
   case rootSelSet of
     GV.RQuery selSet ->
       runInTx $ encJFromJValue <$> GV.traverseObjectSelectionSet selSet (explainField userInfo gCtx sqlGenCtx actionExecuter)
     GV.RMutation _ ->
       throw400 InvalidParams "only queries can be explained"
-    GV.RSubscription alias rootField -> do
+    GV.RSubscription fields -> do
       (plan, _) <- E.getSubsOp pgExecCtx gCtx sqlGenCtx userInfo
-                     queryReusability actionExecuter alias rootField
+                     queryReusability actionExecuter fields
       runInTx $ encJFromJValue <$> E.explainLiveQueryPlan plan
   where
     apiType = bool E.GATGeneral E.GATRelay $ fromMaybe False maybeIsRelay
diff --git a/server/src-lib/Hasura/GraphQL/NormalForm.hs b/server/src-lib/Hasura/GraphQL/NormalForm.hs
index 3436b2d2fd4e6..58e20980168ad 100644
--- a/server/src-lib/Hasura/GraphQL/NormalForm.hs
+++ b/server/src-lib/Hasura/GraphQL/NormalForm.hs
@@ -1,5 +1,5 @@
+{-# LANGUAGE RecordWildCards        #-}
 {-# LANGUAGE TypeFamilyDependencies #-}
-{-# LANGUAGE RecordWildCards #-}
 module Hasura.GraphQL.NormalForm
   ( Selection(..)
   , NormalizedSelection
@@ -7,7 +7,7 @@ module Hasura.GraphQL.NormalForm
   , NormalizedField
   , SelectionSet(..)
   , RootSelectionSet(..)
-  , toGraphQLOperation
+  -- , toGraphQLOperation
   , ArgsMap
   , Field(..)
   , Typename(..)
@@ -19,6 +19,7 @@ module Hasura.GraphQL.NormalForm
   , ObjectSelectionSetMap
   , traverseObjectSelectionSet
   , InterfaceSelectionSet
+  , asInterfaceSelectionSet
   , getMemberSelectionSet
   , UnionSelectionSet
   , ScopedSelectionSet(..)
@@ -47,10 +48,10 @@ import qualified Data.HashMap.Strict                 as Map
 import qualified Data.HashMap.Strict.InsOrd.Extended as OMap
 import qualified Language.GraphQL.Draft.Syntax       as G
 
+import qualified Hasura.RQL.Types.Column             as RQL
+import qualified Hasura.RQL.Types.Error              as RQL
 import           Hasura.SQL.Types
 import           Hasura.SQL.Value
-import qualified Hasura.RQL.Types.Column       as RQL
-import qualified Hasura.RQL.Types.Error        as RQL
 
 data Selection f s
   = SelectionField !G.Alias !f
@@ -109,31 +110,29 @@ type UnionSelectionSet = ScopedSelectionSet Typename
 data RootSelectionSet
   = RQuery !ObjectSelectionSet
   | RMutation !ObjectSelectionSet
-  | RSubscription !G.Alias !Field
+  | RSubscription !ObjectSelectionSet
   deriving (Show, Eq)
 
-toGraphQLOperation :: RootSelectionSet -> G.ExecutableDefinition
-toGraphQLOperation = \case
-  RQuery selectionSet ->
-    mkExecutableDefinition G.OperationTypeQuery $
-    toGraphQLSelectionSet $ SelectionSetObject selectionSet
-  RMutation selectionSet ->
-    mkExecutableDefinition G.OperationTypeQuery $
-    toGraphQLSelectionSet $ SelectionSetObject selectionSet
-  RSubscription alias field ->
-    mkExecutableDefinition G.OperationTypeSubscription $
-    toGraphQLSelectionSet $ SelectionSetObject $ ObjectSelectionSet $
-      AliasedFields $ OMap.singleton alias field
-  where
-    mkExecutableDefinition operationType selectionSet =
-      G.ExecutableDefinitionOperation $ G.OperationDefinitionTyped $
-      G.TypedOperationDefinition
-        { G._todName = Nothing -- TODO, store the name too?
-        , G._todDirectives = []
-        , G._todType = operationType
-        , G._todVariableDefinitions = []
-        , G._todSelectionSet = selectionSet
-        }
+-- toGraphQLOperation :: RootSelectionSet -> G.ExecutableDefinition
+-- toGraphQLOperation = \case
+--   RQuery selectionSet ->
+--     mkExecutableDefinition G.OperationTypeQuery $
+--     toGraphQLSelectionSet $ SelectionSetObject selectionSet
+--   RMutation selectionSet ->
+--     mkExecutableDefinition G.OperationTypeQuery $
+--     toGraphQLSelectionSet $ SelectionSetObject selectionSet
+--   RSubscription opDef _ ->
+--     G.ExecutableDefinitionOperation $ G.OperationDefinitionTyped opDef
+--   where
+--     mkExecutableDefinition operationType selectionSet =
+--       G.ExecutableDefinitionOperation $ G.OperationDefinitionTyped $
+--       G.TypedOperationDefinition
+--         { G._todName = Nothing -- TODO, store the name too?
+--         , G._todDirectives = []
+--         , G._todType = operationType
+--         , G._todVariableDefinitions = []
+--         , G._todSelectionSet = selectionSet
+--         }
 
 
 data SelectionSet
@@ -165,6 +164,12 @@ getInterfaceSelectionSet = \case
   SelectionSetInterface s -> pure s
   _ -> Nothing
 
+asInterfaceSelectionSet
+  :: (MonadError RQL.QErr m) => SelectionSet -> m InterfaceSelectionSet
+asInterfaceSelectionSet selectionSet =
+  onNothing (getInterfaceSelectionSet selectionSet) $
+  RQL.throw500 "expecting InterfaceSelectionSet"
+
 type ArgsMap = Map.HashMap G.Name AnnInpVal
 
 data Field
diff --git a/server/src-lib/Hasura/GraphQL/RelaySchema.hs b/server/src-lib/Hasura/GraphQL/RelaySchema.hs
index 01ecebfa14609..ac17acf23aaab 100644
--- a/server/src-lib/Hasura/GraphQL/RelaySchema.hs
+++ b/server/src-lib/Hasura/GraphQL/RelaySchema.hs
@@ -4,8 +4,8 @@ import           Control.Lens.Extended          hiding (op)
 
 import qualified Data.HashMap.Strict            as Map
 import qualified Data.HashSet                   as Set
-
 import qualified Data.Text                      as T
+import qualified Language.GraphQL.Draft.Syntax  as G
 
 import           Hasura.GraphQL.Context
 import           Hasura.GraphQL.Resolve.Types
@@ -24,31 +24,49 @@ import           Hasura.GraphQL.Schema.Function
 import           Hasura.GraphQL.Schema.OrderBy
 import           Hasura.GraphQL.Schema.Select
 
+mkNodeInterface :: [QualifiedTable] -> IFaceTyInfo
+mkNodeInterface relayTableNames =
+  let description = G.Description "An object with globally unique ID"
+  in IFaceTyInfo (Just description) nodeType (mapFromL _fiName [idField]) $
+     Set.fromList $ map mkTableTy relayTableNames
+  where
+    idField =
+        let description = G.Description "A globally unique identifier"
+        in mkHsraObjFldInfo (Just description) "id" mempty nodeIdType
+
 mkRelayGCtxMap
   :: forall m. (MonadError QErr m)
   => TableCache -> FunctionCache -> m GCtxMap
 mkRelayGCtxMap tableCache functionCache = do
-  typesMapL <- mapM (mkRelayGCtxMapTable tableCache functionCache) $
-               filter (tableFltr . _tiCoreInfo) $ Map.elems tableCache
+  typesMapL <- mapM (mkRelayGCtxMapTable tableCache functionCache) relayTables
   typesMap <- combineTypes typesMapL
   let gCtxMap  = flip Map.map typesMap $
                  \(ty, flds) -> mkGCtx ty flds mempty
   pure $ Map.map (flip RoleContext Nothing) gCtxMap
   where
-    tableFltr ti = not (isSystemDefined $ _tciSystemDefined ti) && isValidObjectName (_tciName ti)
+    relayTables =
+      filter (tableFltr . _tiCoreInfo) $ Map.elems tableCache
+
+    tableFltr ti =
+      not (isSystemDefined $ _tciSystemDefined ti)
+      && isValidObjectName (_tciName ti)
+      && isJust (_tciPrimaryKey ti)
 
     combineTypes
       :: [Map.HashMap RoleName (TyAgg, RootFields)]
       -> m (Map.HashMap RoleName (TyAgg, RootFields))
     combineTypes maps = do
       let listMap = foldr (Map.unionWith (++) . Map.map pure) mempty maps
-      flip Map.traverseWithKey listMap $ \_ typeList -> do
-        let tyAgg = mconcat $ map (^. _1) typeList
-        rootFields <- combineRootFields $ map (^. _2) typeList
+      flip Map.traverseWithKey listMap $ \roleName typeList -> do
+        let relayTableNames = map (_tciName . _tiCoreInfo) relayTables
+            tyAgg = addTypeInfoToTyAgg
+                    (TIIFace $ mkNodeInterface relayTableNames) $
+                    mconcat $ map (^. _1) typeList
+        rootFields <- combineRootFields roleName $ map (^. _2) typeList
         pure (tyAgg, rootFields)
 
-    combineRootFields :: [RootFields] -> m RootFields
-    combineRootFields rootFields = do
+    combineRootFields :: RoleName -> [RootFields] -> m RootFields
+    combineRootFields roleName rootFields = do
       let duplicateQueryFields = duplicates $
             concatMap (Map.keys . _rootQueryFields) rootFields
           duplicateMutationFields = duplicates $
@@ -63,7 +81,7 @@ mkRelayGCtxMap tableCache functionCache = do
         throw400 Unexpected $ "following mutation root fields are duplicated: "
         <> showNames duplicateMutationFields
 
-      pure $ mconcat rootFields
+      pure $ mconcat $ mkNodeQueryRootFields roleName relayTables : rootFields
 
 mkRelayGCtxMapTable
   :: (MonadError QErr m)
@@ -181,7 +199,8 @@ mkRelayGCtxRole' tn descM selPermM pkeyCols funcs =
     -- table obj
     selectObjects = case selPermM of
       Just (_, selFlds) ->
-        [ mkTableObj tn True descM selFlds
+        [ (mkRelayTableObj tn descM selFlds)
+          {_otiImplIFaces = Set.singleton nodeType}
         , mkTableEdgeObj tn
         , mkTableConnectionObj tn
         ]
@@ -217,7 +236,10 @@ mkRelayGCtxRole' tn descM selPermM pkeyCols funcs =
           compFldsObjs = bool (map mkCompObjFld compAggregateOps) [] $ null compCols
       in numFldsObjs <> compFldsObjs
     -- the fields used in table object
-    selObjFldsM = mkFldMap (mkTableTy tn) <$> selFldsM
+    nodeFieldM =  RFNodeId tn . _pkColumns <$> pkeyCols
+    selObjFldsM = mkFldMap (mkTableTy tn) <$> selFldsM >>=
+                  \fm -> nodeFieldM <&> \nodeField ->
+                    Map.insert (mkTableTy tn, "id") nodeField fm
     -- the scalar set for table_by_pk arguments
     selByPkScalarSet = pkeyCols ^.. folded.to _pkColumns.folded.to pgiType._PGColumnScalar
 
@@ -238,6 +260,16 @@ mkRelayGCtxRole' tn descM selPermM pkeyCols funcs =
     computedFieldFuncArgsInps = map (TIInpObj . fst) computedFieldReqTypes
     computedFieldFuncArgScalars = Set.fromList $ concatMap snd computedFieldReqTypes
 
+mkSelectOpCtx
+  :: QualifiedTable
+  -> [PGColumnInfo]
+  -> (AnnBoolExpPartialSQL, Maybe Int, [T.Text]) -- select filter
+  -> SelOpCtx
+mkSelectOpCtx tn allCols (fltr, pLimit, hdrs) =
+  SelOpCtx tn hdrs colGNameMap fltr pLimit
+  where
+    colGNameMap = mkPGColGNameMap allCols
+
 getRelayRootFldsRole'
   :: QualifiedTable
   -> Maybe (PrimaryKey PGColumnInfo)
@@ -267,7 +299,7 @@ getRelayRootFldsRole' tn primaryKey fields funcs selM =
       (mkSelFldConnection Nothing) selFltr pLimit hdrs
 
     selFldHelper f g pFltr pLimit hdrs =
-      ( f $ SelOpCtx tn hdrs colGNameMap pFltr pLimit
+      ( f $ mkSelectOpCtx tn (getCols fields) (pFltr, pLimit, hdrs)
       , g tn
       )
 
@@ -279,3 +311,33 @@ getRelayRootFldsRole' tn primaryKey fields funcs selM =
       ( f $ FuncQOpCtx (fiName fi) (mkFuncArgItemSeq fi) hdrs colGNameMap pFltr pLimit
       , g fi $ fiDescription fi
       )
+
+mkNodeQueryRootFields :: RoleName -> [TableInfo] -> RootFields
+mkNodeQueryRootFields roleName relayTables =
+  RootFields (mapFromL (_fiName . snd) [nodeQueryDet]) mempty
+  where
+    nodeQueryDet =
+      ( QCNodeSelect nodeSelMap
+      , nodeQueryField
+      )
+
+    nodeQueryField =
+      let nodeParams = fromInpValL $ pure $
+                       InpValInfo (Just $ G.Description "A globally unique id")
+                       "id" Nothing nodeIdType
+      in mkHsraObjFldInfo Nothing "node" nodeParams $ G.toGT nodeType
+
+    nodeSelMap =
+      Map.fromList $ flip mapMaybe relayTables $ \table ->
+      let tableName = _tciName $ _tiCoreInfo table
+          allColumns = getCols $ _tciFieldInfoMap $ _tiCoreInfo table
+          selectPermM = _permSel <$> Map.lookup roleName
+                       (_tiRolePermInfoMap table)
+          permDetailsM = join selectPermM <&> \perm ->
+            ( spiFilter perm
+            , spiLimit perm
+            , spiRequiredHeaders perm
+            )
+          adminPermDetails = (noFilter, Nothing, [])
+      in (mkTableTy tableName,) . mkSelectOpCtx tableName allColumns
+         <$> bool permDetailsM (Just adminPermDetails) (isAdmin roleName)
diff --git a/server/src-lib/Hasura/GraphQL/Resolve.hs b/server/src-lib/Hasura/GraphQL/Resolve.hs
index 2efe8d5fc25a1..ac6132b6f487d 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve.hs
@@ -38,12 +38,14 @@ import qualified Hasura.GraphQL.Resolve.Insert     as RI
 import qualified Hasura.GraphQL.Resolve.Introspect as RIntro
 import qualified Hasura.GraphQL.Resolve.Mutation   as RM
 import qualified Hasura.GraphQL.Resolve.Select     as RS
+import qualified Hasura.GraphQL.Schema.Common      as GS
 import qualified Hasura.GraphQL.Validate           as V
 import qualified Hasura.RQL.DML.Select             as DS
 import qualified Hasura.SQL.DML                    as S
 
 data QueryRootFldAST v
-  = QRFPk !(DS.AnnSimpleSelG v)
+  = QRFNode !(DS.AnnSimpleSelG v)
+  | QRFPk !(DS.AnnSimpleSelG v)
   | QRFSimple !(DS.AnnSimpleSelG v)
   | QRFAgg !(DS.AnnAggregateSelectG v)
   | QRFConnection !(DS.ConnectionSelect v)
@@ -61,6 +63,7 @@ traverseQueryRootFldAST
   -> QueryRootFldAST a
   -> f (QueryRootFldAST b)
 traverseQueryRootFldAST f = \case
+  QRFNode s                -> QRFNode <$> DS.traverseAnnSimpleSelect f s
   QRFPk s                  -> QRFPk <$> DS.traverseAnnSimpleSelect f s
   QRFSimple s              -> QRFSimple <$> DS.traverseAnnSimpleSelect f s
   QRFAgg s                 -> QRFAgg <$> DS.traverseAnnAggregateSelect f s
@@ -71,6 +74,7 @@ traverseQueryRootFldAST f = \case
 
 toPGQuery :: QueryRootFldResolved -> Q.Query
 toPGQuery = \case
+  QRFNode s                -> Q.fromBuilder $ toSQL $ DS.mkSQLSelect DS.JASSingleObject s
   QRFPk s                  -> Q.fromBuilder $ toSQL $ DS.mkSQLSelect DS.JASSingleObject s
   QRFSimple s              -> Q.fromBuilder $ toSQL $ DS.mkSQLSelect DS.JASMultipleRows s
   QRFAgg s                 -> Q.fromBuilder $ toSQL $ DS.mkAggregateSelect s
@@ -106,6 +110,13 @@ queryFldToPGAST fld actionExecuter = do
   opCtx <- getOpCtx $ V._fName fld
   userInfo <- asks getter
   case opCtx of
+    QCNodeSelect nodeSelectMap -> do
+      NodeIdData table pkeyColumnValues <- RS.resolveNodeId fld
+      case Map.lookup (GS.mkTableTy table) nodeSelectMap of
+        Nothing       -> throwVE $ "table " <> table <<> " not found"
+        Just selOpCtx -> do
+          validateHdrs userInfo (_socHeaders selOpCtx)
+          QRFNode <$> RS.convertNodeSelect selOpCtx pkeyColumnValues fld
     QCSelect ctx -> do
       validateHdrs userInfo (_socHeaders ctx)
       QRFSimple <$> RS.convertSelect ctx fld
@@ -130,13 +141,11 @@ queryFldToPGAST fld actionExecuter = do
       -- an SQL query, but in case of query actions it's converted into JSON
       -- and included in the action's webhook payload.
       markNotReusable
-      let f = case jsonAggType of
+      let jsonAggType = RA.mkJsonAggSelect $ _saecOutputType ctx
+          f = case jsonAggType of
              DS.JASMultipleRows -> QRFActionExecuteList
              DS.JASSingleObject -> QRFActionExecuteObject
       f <$> actionExecuter (RA.resolveActionQuery fld ctx (_uiSession userInfo))
-      where
-        outputType = _saecOutputType ctx
-        jsonAggType = RA.mkJsonAggSelect outputType
     QCSelectConnection pk ctx ->
       QRFConnection <$> RS.convertConnectionSelect pk ctx fld
     QCFuncConnection pk ctx ->
@@ -200,6 +209,7 @@ getOpCtx f = do
 
 toSQLFromItem :: S.Alias -> QueryRootFldResolved -> S.FromItem
 toSQLFromItem alias = \case
+  QRFNode s                -> fromSelect $ DS.mkSQLSelect DS.JASSingleObject s
   QRFPk s                  -> fromSelect $ DS.mkSQLSelect DS.JASSingleObject s
   QRFSimple s              -> fromSelect $ DS.mkSQLSelect DS.JASMultipleRows s
   QRFAgg s                 -> fromSelect $ DS.mkAggregateSelect s
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/BoolExp.hs b/server/src-lib/Hasura/GraphQL/Resolve/BoolExp.hs
index 48680e47310b4..474eaed598d7f 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/BoolExp.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/BoolExp.hs
@@ -169,6 +169,8 @@ parseColExp nt n val = do
         fmapAnnBoolExp partialSQLExpToUnresolvedVal permExp
     RFComputedField _ -> throw500
           "computed fields are not allowed in bool_exp"
+    RFNodeId _ _      -> throw500
+      "node id is not allowed in bool_exp"
 
 parseBoolExp
   :: ( MonadReusability m
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Context.hs b/server/src-lib/Hasura/GraphQL/Resolve/Context.hs
index 0178184646e0d..3aac7d62389a7 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Context.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Context.hs
@@ -33,21 +33,21 @@ module Hasura.GraphQL.Resolve.Context
 import           Data.Has
 import           Hasura.Prelude
 
-import qualified Data.HashMap.Strict           as Map
-import qualified Data.Sequence                 as Seq
-import qualified Database.PG.Query             as Q
-import qualified Language.GraphQL.Draft.Syntax as G
+import qualified Data.HashMap.Strict                  as Map
+import qualified Data.Sequence                        as Seq
+import qualified Database.PG.Query                    as Q
+import qualified Language.GraphQL.Draft.Syntax        as G
 
 import           Hasura.GraphQL.Resolve.Types
 import           Hasura.GraphQL.Utils
 import           Hasura.GraphQL.Validate.SelectionSet
 import           Hasura.GraphQL.Validate.Types
-import           Hasura.RQL.DML.Internal       (currentSession, sessVarFromCurrentSetting)
+import           Hasura.RQL.DML.Internal              (currentSession, sessVarFromCurrentSetting)
 import           Hasura.RQL.Types
 import           Hasura.SQL.Types
 import           Hasura.SQL.Value
 
-import qualified Hasura.SQL.DML                as S
+import qualified Hasura.SQL.DML                       as S
 
 getFldInfo
   :: (MonadError QErr m, MonadReader r m, Has FieldMap r)
@@ -68,6 +68,7 @@ getPGColInfo nt n = do
     RFPGColumn pgColInfo -> return pgColInfo
     RFRelationship _     -> throw500 $ mkErrMsg "relation"
     RFComputedField _    -> throw500 $ mkErrMsg "computed field"
+    RFNodeId _ _         -> throw500 $ mkErrMsg "node id"
   where
     mkErrMsg ty =
       "found " <> ty <> " when expecting pgcolinfo for "
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Introspect.hs b/server/src-lib/Hasura/GraphQL/Resolve/Introspect.hs
index 79d377b221c10..81d349442755d 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Introspect.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Introspect.hs
@@ -44,7 +44,7 @@ withSubFields
   -> m J.Object
 withSubFields selSet fn = do
   objectSelectionSet <- asObjectSelectionSet selSet
-  fmap Map.fromList $ traverseObjectSelectionSet objectSelectionSet fn
+  Map.fromList <$> traverseObjectSelectionSet objectSelectionSet fn
   -- val <- fn fld
   -- return (G.unName $ G.unAlias $ _fAlias fld, val)
 
@@ -146,7 +146,7 @@ ifaceR'
   => IFaceTyInfo
   -> Field
   -> m J.Object
-ifaceR' i@(IFaceTyInfo descM n flds implementations) fld = do
+ifaceR' i@(IFaceTyInfo descM n flds _) fld = do
   dummyReadIncludeDeprecated fld
   withSubFields (_fSelSet fld) $ \subFld ->
     case _fName subFld of
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Select.hs b/server/src-lib/Hasura/GraphQL/Resolve/Select.hs
index c02b345c3879a..e0aec9c388a68 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Select.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Select.hs
@@ -8,6 +8,8 @@ module Hasura.GraphQL.Resolve.Select
   , convertFuncQueryAgg
   , parseColumns
   , processTableSelectionSet
+  , resolveNodeId
+  , convertNodeSelect
   , AnnSimpleSelect
   ) where
 
@@ -24,7 +26,6 @@ import qualified Data.HashMap.Strict.InsOrd           as OMap
 import qualified Data.List.NonEmpty                   as NE
 import qualified Data.Sequence                        as Seq
 import qualified Data.Text                            as T
-import qualified Data.Text.Conversions                as TC
 import qualified Language.GraphQL.Draft.Syntax        as G
 
 import qualified Hasura.RQL.DML.Select                as RS
@@ -34,6 +35,7 @@ import           Hasura.GraphQL.Resolve.BoolExp
 import           Hasura.GraphQL.Resolve.Context
 import           Hasura.GraphQL.Resolve.InputValue
 import           Hasura.GraphQL.Schema                (isAggregateField)
+import           Hasura.GraphQL.Schema.Common         (mkTableTy)
 import           Hasura.GraphQL.Validate.SelectionSet
 import           Hasura.GraphQL.Validate.Types
 import           Hasura.RQL.DML.Internal              (onlyPositiveInt)
@@ -113,6 +115,7 @@ processTableSelectionSet fldTy flds =
       _ -> do
         fldInfo <- getFldInfo fldTy fldName
         case fldInfo of
+          RFNodeId tn pkeys -> pure $ RS.AFNodeId tn pkeys
           RFPGColumn colInfo ->
             RS.mkAnnColumnField colInfo <$> argsToColumnOp (_fArguments fld)
           RFComputedField computedField ->
@@ -550,8 +553,8 @@ parseConnectionArgs pKeyColumns args = do
   maybeSplit <- case (Map.lookup "after" args, Map.lookup "before" args) of
     (Nothing, Nothing) -> pure Nothing
     (Just _, Just _)   -> throwVE "\"after\" and \"before\" are not allowed at once"
-    (Just v, Nothing)  -> fmap ((RS.CSKAfter,) . TC.convertText) <$> asPGColTextM v
-    (Nothing, Just v)  -> fmap ((RS.CSKBefore,) . TC.convertText) <$> asPGColTextM v
+    (Just v, Nothing)  -> fmap ((RS.CSKAfter,) . base64Decode) <$> asPGColTextM v
+    (Nothing, Just v)  -> fmap ((RS.CSKBefore,) . base64Decode) <$> asPGColTextM v
 
   let ordByExpM = NE.nonEmpty =<< ordByExpML
       tableArgs = RS.SelectArgs whereExpM ordByExpM Nothing Nothing Nothing
@@ -562,12 +565,11 @@ parseConnectionArgs pKeyColumns args = do
     validateConnectionSplit
       :: Maybe (NonEmpty (RS.AnnOrderByItemG UnresolvedVal))
       -> RS.ConnectionSplitKind
-      -> Maybe (TC.Base64 BL.ByteString)
+      -> BL.ByteString
       -> m (NonEmpty (RS.ConnectionSplit UnresolvedVal))
-    validateConnectionSplit maybeOrderBys splitKind maybeCursorSplit = do
-      cursorSplit <- maybe throwInvalidCursor pure maybeCursorSplit
+    validateConnectionSplit maybeOrderBys splitKind cursorSplit = do
       cursorValue <- either (const throwInvalidCursor) pure $
-                      J.eitherDecode $ TC.unBase64 cursorSplit
+                      J.eitherDecode cursorSplit
       case maybeOrderBys of
         Nothing -> forM pKeyColumns $
           \pgColumnInfo -> do
@@ -735,3 +737,54 @@ convertConnectionFuncQuery pkCols funcOpCtx fld =
     fromConnectionField selectFrom pkCols permFilter permLimit fld
   where
     FuncQOpCtx qf argSeq _ _ permFilter permLimit = funcOpCtx
+
+resolveNodeId
+  :: forall m. ( MonadError QErr m
+               , MonadReusability m
+               )
+  => Field -> m NodeIdData
+resolveNodeId field =
+  withPathK "selectionSet" $ fieldAsPath field $ do
+    nodeIdText <- asPGColText =<< getArg (_fArguments field) "id"
+    either (const throwInvalidNodeId) pure $
+      J.eitherDecode $ base64Decode nodeIdText
+  where
+    throwInvalidNodeId = throwVE "the node id is invalid"
+
+convertNodeSelect
+  :: ( MonadReusability m
+     , MonadError QErr m
+     , MonadReader r m
+     , Has FieldMap r
+     , Has OrdByCtx r
+     , Has SQLGenCtx r
+     )
+  => SelOpCtx
+  -> Map.HashMap PGCol J.Value
+  -> Field
+  -> m (RS.AnnSimpleSelG UnresolvedVal)
+convertNodeSelect selOpCtx pkeyColumnValues field =
+  withPathK "selectionSet" $ fieldAsPath field $ do
+    -- Parse selection set as interface
+    ifaceSelectionSet <- asInterfaceSelectionSet $ _fSelSet field
+    let tableObjectType = mkTableTy table
+        selSet = getMemberSelectionSet tableObjectType ifaceSelectionSet
+        unresolvedPermFilter = fmapAnnBoolExp partialSQLExpToUnresolvedVal permFilter
+        tablePerm = RS.TablePerm unresolvedPermFilter permLimit
+    -- Resolve the table selection set
+    annFields <- processTableSelectionSet tableObjectType selSet
+    -- Resolve the Node id primary key column values
+    unresolvedPkeyValues <- flip Map.traverseWithKey pkeyColumnValues $
+      \pgColumn jsonValue -> case Map.lookup pgColumn pgColumnMap of
+        Nothing -> throwVE $ "column " <> pgColumn <<> " not found"
+        Just columnInfo -> (,columnInfo) . UVPG . AnnPGVal Nothing False <$>
+                           parsePGScalarValue (pgiType columnInfo) jsonValue
+    -- Generate the bool expression from the primary key column values
+    let pkeyBoolExp = BoolAnd $ flip map (Map.elems unresolvedPkeyValues) $
+          \(unresolvedValue, columnInfo) -> (BoolFld . AVCol columnInfo) [AEQ True unresolvedValue]
+        selectArgs = RS.noSelectArgs{RS._saWhere = Just pkeyBoolExp}
+    strfyNum <- stringifyNum <$> asks getter
+    pure $ RS.AnnSelectG annFields (RS.FromTable table) tablePerm selectArgs strfyNum
+  where
+    SelOpCtx table _ allColumns permFilter permLimit = selOpCtx
+    pgColumnMap = mapFromL pgiColumn $ Map.elems allColumns
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Types.hs b/server/src-lib/Hasura/GraphQL/Resolve/Types.hs
index 1e08b88961206..c07f19dc4911f 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Types.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Types.hs
@@ -7,6 +7,9 @@ module Hasura.GraphQL.Resolve.Types
 import           Control.Lens.TH
 import           Hasura.Prelude
 
+import qualified Data.Aeson                     as J
+import qualified Data.Aeson.Casing              as J
+import qualified Data.Aeson.TH                  as J
 import qualified Data.HashMap.Strict            as Map
 import qualified Data.Sequence                  as Seq
 import qualified Data.Text                      as T
@@ -27,8 +30,11 @@ import           Hasura.SQL.Value
 
 import qualified Hasura.SQL.DML                 as S
 
+type NodeSelectMap = Map.HashMap G.NamedType SelOpCtx
+
 data QueryCtx
-  = QCSelect !SelOpCtx
+  = QCNodeSelect !NodeSelectMap
+  | QCSelect !SelOpCtx
   | QCSelectConnection !(NonEmpty PGColumnInfo) !SelOpCtx
   | QCSelectPkey !SelPkOpCtx
   | QCSelectAgg !SelOpCtx
@@ -174,6 +180,7 @@ data ResolveField
   = RFPGColumn !PGColumnInfo
   | RFRelationship !RelationshipField
   | RFComputedField !ComputedField
+  | RFNodeId !QualifiedTable !(NonEmpty PGColumnInfo)
   deriving (Show, Eq)
 
 type FieldMap = Map.HashMap (G.NamedType, G.Name) ResolveField
@@ -253,6 +260,13 @@ data InputFunctionArgument
   | IFAUnknown !FunctionArgItem -- ^ Unknown value, need to be parsed
   deriving (Show, Eq)
 
+data NodeIdData
+  = NodeIdData
+  { _nidTable   :: !QualifiedTable
+  , _nidColumns :: !(Map.HashMap PGCol J.Value)
+  } deriving (Show, Eq)
+$(J.deriveFromJSON (J.aesonDrop 4 J.snakeCase) ''NodeIdData)
+
 -- template haskell related
 $(makePrisms ''ResolveField)
 $(makeLenses ''ComputedField)
diff --git a/server/src-lib/Hasura/GraphQL/Schema.hs b/server/src-lib/Hasura/GraphQL/Schema.hs
index d4b91b156d243..45415d3bf9fbc 100644
--- a/server/src-lib/Hasura/GraphQL/Schema.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema.hs
@@ -253,7 +253,7 @@ mkGCtxRole' tn descM insPermM selPermM updColsM delPermM pkeyCols constraints vi
     -- table obj
     selectObjects = case selPermM of
       Just (_, selFlds) ->
-        [ mkTableObj tn False descM selFlds
+        [ mkTableObj tn descM selFlds
         ]
       Nothing -> []
 
diff --git a/server/src-lib/Hasura/GraphQL/Schema/Common.hs b/server/src-lib/Hasura/GraphQL/Schema/Common.hs
index dce7e0eb051ec..8c6a858c0ffb2 100644
--- a/server/src-lib/Hasura/GraphQL/Schema/Common.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/Common.hs
@@ -32,6 +32,9 @@ module Hasura.GraphQL.Schema.Common
 
   , numAggregateOps
   , compAggregateOps
+
+  , nodeType
+  , nodeIdType
   ) where
 
 import qualified Data.HashMap.Strict           as Map
@@ -152,3 +155,11 @@ numAggregateOps = [ "sum", "avg", "stddev", "stddev_samp", "stddev_pop"
 
 compAggregateOps :: [G.Name]
 compAggregateOps = ["max", "min"]
+
+nodeType :: G.NamedType
+nodeType =
+  G.NamedType "Node"
+
+nodeIdType :: G.GType
+nodeIdType =
+  G.toGT $ G.toNT $ G.NamedType "ID"
diff --git a/server/src-lib/Hasura/GraphQL/Schema/OrderBy.hs b/server/src-lib/Hasura/GraphQL/Schema/OrderBy.hs
index c8771cb521454..a4cac50aa9a1d 100644
--- a/server/src-lib/Hasura/GraphQL/Schema/OrderBy.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/OrderBy.hs
@@ -65,9 +65,9 @@ mkTabAggregateOpOrdByInpObjs
   -> ([PGColumnInfo], [G.Name])
   -> ([PGColumnInfo], [G.Name])
   -> [InpObjTyInfo]
-mkTabAggregateOpOrdByInpObjs tn (numCols, numAggregateOps) (compCols, compAggregateOps) =
-  mapMaybe (mkInpObjTyM numCols) numAggregateOps
-  <> mapMaybe (mkInpObjTyM compCols) compAggregateOps
+mkTabAggregateOpOrdByInpObjs tn (numCols, numericAggregateOps) (compCols, compareAggregateOps) =
+  mapMaybe (mkInpObjTyM numCols) numericAggregateOps
+  <> mapMaybe (mkInpObjTyM compCols) compareAggregateOps
   where
 
     mkDesc (G.Name op) =
@@ -97,15 +97,15 @@ mkTabAggOrdByInpObj
   -> ([PGColumnInfo], [G.Name])
   -> ([PGColumnInfo], [G.Name])
   -> InpObjTyInfo
-mkTabAggOrdByInpObj tn (numCols, numAggregateOps) (compCols, compAggregateOps) =
+mkTabAggOrdByInpObj tn (numCols, numericAggregateOps) (compCols, compareAggregateOps) =
   mkHsraInpTyInfo (Just desc) (mkTabAggOrdByTy tn) $ fromInpValL $
   numOpOrdBys <> compOpOrdBys <> [countInpVal]
   where
     desc = G.Description $
       "order by aggregate values of table " <>> tn
 
-    numOpOrdBys = bool (map mkInpValInfo numAggregateOps) [] $ null numCols
-    compOpOrdBys = bool (map mkInpValInfo compAggregateOps) [] $ null compCols
+    numOpOrdBys = bool (map mkInpValInfo numericAggregateOps) [] $ null numCols
+    compOpOrdBys = bool (map mkInpValInfo compareAggregateOps) [] $ null compCols
     mkInpValInfo op = InpValInfo Nothing op Nothing $ G.toGT $
                      mkTabAggregateOpOrdByTy tn op
 
diff --git a/server/src-lib/Hasura/GraphQL/Schema/Select.hs b/server/src-lib/Hasura/GraphQL/Schema/Select.hs
index f4a7d63004f51..d36239e3a581c 100644
--- a/server/src-lib/Hasura/GraphQL/Schema/Select.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/Select.hs
@@ -1,5 +1,6 @@
 module Hasura.GraphQL.Schema.Select
   ( mkTableObj
+  , mkRelayTableObj
   , mkTableAggObj
   , mkSelColumnTy
   , mkTableAggregateFieldsObj
@@ -206,11 +207,10 @@ type table {
 -}
 mkTableObj
   :: QualifiedTable
-  -> Bool
   -> Maybe PGDescription
   -> [SelField]
   -> ObjTyInfo
-mkTableObj tn isRelay descM allowedFlds =
+mkTableObj tn descM allowedFlds =
   mkObjTyInfo (Just desc) (mkTableTy tn) Set.empty (mapFromL _fiName flds) TLHasuraType
   where
     flds = pgColumnFields <> relFlds <> computedFlds
@@ -218,7 +218,27 @@ mkTableObj tn isRelay descM allowedFlds =
     relFlds = concatMap mkRelationshipField' $ getRelationshipFields allowedFlds
     computedFlds = map mkComputedFieldFld $ getComputedFields allowedFlds
     mkRelationshipField' (RelationshipFieldInfo relInfo allowAgg _ _ _ maybePkCols isNullable) =
-      mkRelationshipField allowAgg relInfo isRelay maybePkCols isNullable
+      mkRelationshipField allowAgg relInfo False maybePkCols isNullable
+    desc = mkDescriptionWith descM $ "columns and relationships of " <>> tn
+
+mkRelayTableObj
+  :: QualifiedTable
+  -> Maybe PGDescription
+  -> [SelField]
+  -> ObjTyInfo
+mkRelayTableObj tn descM allowedFlds =
+  mkObjTyInfo (Just desc) (mkTableTy tn) Set.empty (mapFromL _fiName flds) TLHasuraType
+  where
+    flds = nodeIdField:pgColumnFields <> relFlds <> computedFlds
+    nodeIdField = mkHsraObjFldInfo Nothing "id" mempty nodeIdType
+    pgColumnFields = map mkPGColFld $
+                     -- Remove "id" column
+                     filter ((/=) "id" . getPGColTxt . pgiColumn) $
+                     getPGColumnFields allowedFlds
+    relFlds = concatMap mkRelationshipField' $ getRelationshipFields allowedFlds
+    computedFlds = map mkComputedFieldFld $ getComputedFields allowedFlds
+    mkRelationshipField' (RelationshipFieldInfo relInfo allowAgg _ _ _ maybePkCols isNullable) =
+      mkRelationshipField allowAgg relInfo True maybePkCols isNullable
     desc = mkDescriptionWith descM $ "columns and relationships of " <>> tn
 
 {-
diff --git a/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs b/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs
index 650d15099218a..9f18f6e55582f 100644
--- a/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs
+++ b/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs
@@ -8,7 +8,6 @@ import qualified Network.HTTP.Types                     as N
 
 import           Hasura.EncJSON
 import           Hasura.GraphQL.Logging
-import           Hasura.GraphQL.NormalForm
 import           Hasura.GraphQL.Transport.HTTP.Protocol
 import           Hasura.HTTP
 import           Hasura.Prelude
@@ -24,7 +23,6 @@ import qualified Hasura.Logging                         as L
 import qualified Hasura.Server.Telemetry.Counters       as Telem
 import qualified Language.GraphQL.Draft.Syntax          as G
 import qualified Network.HTTP.Types                     as HTTP
-import qualified Language.GraphQL.Draft.Printer.Text    as GP
 
 runGQ
   :: ( HasVersion
@@ -49,17 +47,17 @@ runGQ reqId userInfo reqHdrs apiType req = do
       E.GExPHasura resolvedOp -> do
         (telemTimeIO, telemQueryType, respHdrs, resp) <- runHasuraGQ reqId req userInfo resolvedOp
         return (telemCacheHit, Telem.Local, (telemTimeIO, telemQueryType, HttpResponse resp respHdrs))
-      E.GExPRemote rsi opDef rootSelSet -> do
+      E.GExPRemote rsi opDef _ -> do
         let telemQueryType | G._todType opDef == G.OperationTypeMutation = Telem.Mutation
                            | otherwise = Telem.Query
-            rewrittenQuery =
-              GQLReq { _grQuery = GQLQueryText $ GP.renderExecutableDoc $
-                                  G.ExecutableDocument $ pure $
-                                  toGraphQLOperation rootSelSet
-                     , _grVariables = Nothing
-                     , _grOperationName = Nothing
-                     }
-        (telemTimeIO, resp) <- E.execRemoteGQ reqId userInfo reqHdrs rewrittenQuery rsi opDef
+            -- rewrittenQuery =
+            --   GQLReq { _grQuery = GQLQueryText $ GP.renderExecutableDoc $
+            --                       G.ExecutableDocument $ pure $
+            --                       toGraphQLOperation rootSelSet
+            --          , _grVariables = Nothing
+            --          , _grOperationName = Nothing
+            --          }
+        (telemTimeIO, resp) <- E.execRemoteGQ reqId userInfo reqHdrs req rsi opDef
         return (telemCacheHit, Telem.Remote, (telemTimeIO, telemQueryType, resp))
   let telemTimeIO = convertDuration telemTimeIO_DT
       telemTimeTot = convertDuration telemTimeTot_DT
diff --git a/server/src-lib/Hasura/GraphQL/Validate.hs b/server/src-lib/Hasura/GraphQL/Validate.hs
index 1804f5918e223..66d13c1bc0e71 100644
--- a/server/src-lib/Hasura/GraphQL/Validate.hs
+++ b/server/src-lib/Hasura/GraphQL/Validate.hs
@@ -22,7 +22,6 @@ import           Data.Has
 import qualified Data.HashMap.Strict                    as Map
 import qualified Data.HashMap.Strict.InsOrd.Extended    as OMap
 import qualified Data.HashSet                           as HS
-import qualified Data.Sequence                          as Seq
 import qualified Language.GraphQL.Draft.Syntax          as G
 
 import           Hasura.GraphQL.Schema
@@ -163,16 +162,16 @@ validateGQ (QueryParts opDef opRoot fragDefsL varValsM) = do
   case G._todType opDef of
     G.OperationTypeQuery -> return $ RQuery selSet
     G.OperationTypeMutation -> return $ RMutation selSet
-    G.OperationTypeSubscription -> do
+    G.OperationTypeSubscription ->
       case OMap.toList $ unAliasedFields $ unObjectSelectionSet selSet of
-        []     -> throw500 "empty selset for subscription"
-        ((alias, field):rst) -> do
+        []             -> throw500 "empty selset for subscription"
+        (_:rst) -> do
           -- As an internal testing feature, we support subscribing to multiple
           -- selection sets.  First check if the corresponding directive is set.
-          let multipleAllowed = elem (G.Directive "_multiple_top_level_fields" []) (G._todDirectives opDef)
+          let multipleAllowed = G.Directive "_multiple_top_level_fields" [] `elem` G._todDirectives opDef
           unless (multipleAllowed || null rst) $
             throwVE "subscriptions must select one top level field"
-          return $ RSubscription alias field
+          return $ RSubscription selSet
 
 isQueryInAllowlist :: GQLExecDoc -> HS.HashSet GQLQuery -> Bool
 isQueryInAllowlist q = HS.member gqlQuery
diff --git a/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs b/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs
index 1a78840c26231..64b3972cd7c8c 100644
--- a/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs
+++ b/server/src-lib/Hasura/GraphQL/Validate/SelectionSet.hs
@@ -1,5 +1,5 @@
+{-# LANGUAGE RecordWildCards        #-}
 {-# LANGUAGE TypeFamilyDependencies #-}
-{-# LANGUAGE RecordWildCards #-}
 module Hasura.GraphQL.Validate.SelectionSet
   ( ArgsMap
   , Field(..)
@@ -12,22 +12,24 @@ module Hasura.GraphQL.Validate.SelectionSet
   , RootSelectionSet(..)
   , parseObjectSelectionSet
   , asObjectSelectionSet
+  , asInterfaceSelectionSet
+  , getMemberSelectionSet
   ) where
 
 import           Hasura.Prelude
 
-import qualified Data.Text                           as T
 import qualified Data.HashMap.Strict                 as Map
-import qualified Data.HashSet                        as Set
 import qualified Data.HashMap.Strict.InsOrd.Extended as OMap
-import qualified Language.GraphQL.Draft.Syntax       as G
-import qualified Data.Sequence.NonEmpty              as NE
+import qualified Data.HashSet                        as Set
 import qualified Data.List                           as L
+import qualified Data.Sequence.NonEmpty              as NE
+import qualified Data.Text                           as T
+import qualified Language.GraphQL.Draft.Syntax       as G
 
+import           Hasura.GraphQL.NormalForm
 import           Hasura.GraphQL.Validate.Context
-import           Hasura.GraphQL.Validate.Types
 import           Hasura.GraphQL.Validate.InputValue
-import           Hasura.GraphQL.NormalForm
+import           Hasura.GraphQL.Validate.Types
 import           Hasura.RQL.Types
 import           Hasura.SQL.Value
 
@@ -116,9 +118,12 @@ parseSelectionSet
   => a
   -> G.SelectionSet
   -> m (NormalizedSelectionSet a)
-parseSelectionSet fieldTypeInfo selectionSet =
+parseSelectionSet fieldTypeInfo selectionSet = do
+  visitedFragments <- get
   withPathK "selectionSet" $ do
-    normalizedSelections <- catMaybes <$> mapM (parseSelection fieldTypeInfo) selectionSet
+    -- The visited fragments state shouldn't accumulate over a selection set.
+    normalizedSelections <-
+      catMaybes <$> mapM (parseSelection visitedFragments fieldTypeInfo) selectionSet
     mergeNormalizedSelections normalizedSelections
   where
     mergeNormalizedSelections = mergeNormalizedSelectionSets . map selectionToSelectionSet
@@ -129,27 +134,28 @@ parseSelection
   :: ( MonadReader ValidationCtx m
      , MonadError QErr m
      , MonadReusability m
-     , MonadState [G.Name] m
      , HasSelectionSet a
      )
-  => a -- parent type info
+  => [G.Name]
+  -> a -- parent type info
   -> G.Selection
   -> m (Maybe (NormalizedSelection a))
-parseSelection parentTypeInfo = \case
-  G.SelectionField fld -> withPathK (G.unName $ G._fName fld) $ do
-    let fieldName = G._fName fld
-        fieldAlias = fromMaybe (G.Alias fieldName) $ G._fAlias fld
-    fmap (SelectionField fieldAlias) <$> parseField_ parentTypeInfo fld
-  G.SelectionFragmentSpread (G.FragmentSpread name directives) -> do
-    FragDef _ fragmentTyInfo fragmentSelectionSet <- getFragmentInfo name
-    withPathK (G.unName name) $
-      fmap (SelectionFragmentSpread name) <$>
-      parseFragment parentTypeInfo fragmentTyInfo directives fragmentSelectionSet
-  G.SelectionInlineFragment (G.InlineFragment {..}) -> do
-    let fragmentType = fromMaybe (getTypename parentTypeInfo) _ifTypeCondition
-    fragmentTyInfo <- getFragmentTyInfo fragmentType
-    withPathK "inlineFragment" $ fmap SelectionInlineFragmentSpread <$>
-      parseFragment parentTypeInfo fragmentTyInfo _ifDirectives _ifSelectionSet
+parseSelection visitedFragments parentTypeInfo =
+  flip evalStateT visitedFragments . \case
+    G.SelectionField fld -> withPathK (G.unName $ G._fName fld) $ do
+      let fieldName = G._fName fld
+          fieldAlias = fromMaybe (G.Alias fieldName) $ G._fAlias fld
+      fmap (SelectionField fieldAlias) <$> parseField_ parentTypeInfo fld
+    G.SelectionFragmentSpread (G.FragmentSpread name directives) -> do
+      FragDef _ fragmentTyInfo fragmentSelectionSet <- getFragmentInfo name
+      withPathK (G.unName name) $
+        fmap (SelectionFragmentSpread name) <$>
+        parseFragment parentTypeInfo fragmentTyInfo directives fragmentSelectionSet
+    G.SelectionInlineFragment G.InlineFragment{..} -> do
+      let fragmentType = fromMaybe (getTypename parentTypeInfo) _ifTypeCondition
+      fragmentTyInfo <- getFragmentTyInfo fragmentType
+      withPathK "inlineFragment" $ fmap SelectionInlineFragmentSpread <$>
+        parseFragment parentTypeInfo fragmentTyInfo _ifDirectives _ifSelectionSet
 
 parseFragment
   :: ( MonadReader ValidationCtx m
@@ -193,13 +199,13 @@ parseFragment parentTyInfo fragmentTyInfo directives fragmentSelectionSet = do
     parentTypeMembers = getMemberTypes parentTyInfo
 
     fragmentType = case fragmentTyInfo of
-      FragmentTyObject tyInfo -> getTypename tyInfo
+      FragmentTyObject tyInfo    -> getTypename tyInfo
       FragmentTyInterface tyInfo -> getTypename tyInfo
-      FragmentTyUnion tyInfo -> getTypename tyInfo
+      FragmentTyUnion tyInfo     -> getTypename tyInfo
     fragmentTypeMembers = case fragmentTyInfo of
-      FragmentTyObject tyInfo -> getMemberTypes tyInfo
+      FragmentTyObject tyInfo    -> getMemberTypes tyInfo
       FragmentTyInterface tyInfo -> getMemberTypes tyInfo
-      FragmentTyUnion tyInfo -> getMemberTypes tyInfo
+      FragmentTyUnion tyInfo     -> getMemberTypes tyInfo
 
 class IsField f => MergeableField f where
 
@@ -542,4 +548,3 @@ instance HasSelectionSet UnionTyInfo where
     ScopedSelectionSet (AliasedFields mempty) $
       Map.fromList $ flip map (toList commonTypes) $
       \commonType -> (commonType, getMemberSelectionSet commonType unionSelectionSet)
-
diff --git a/server/src-lib/Hasura/GraphQL/Validate/Types.hs b/server/src-lib/Hasura/GraphQL/Validate/Types.hs
index 80cd32b53780c..55fb217841753 100644
--- a/server/src-lib/Hasura/GraphQL/Validate/Types.hs
+++ b/server/src-lib/Hasura/GraphQL/Validate/Types.hs
@@ -262,7 +262,7 @@ instance Semigroup ObjTyInfo where
 mkObjTyInfo
   :: Maybe G.Description -> G.NamedType
   -> IFacesSet -> ObjFieldMap -> TypeLoc -> ObjTyInfo
-mkObjTyInfo descM ty iFaces flds loc =
+mkObjTyInfo descM ty iFaces flds _ =
   ObjTyInfo descM ty iFaces $ Map.insert (_fiName newFld) newFld flds
   where newFld = typenameFld
 
@@ -278,7 +278,7 @@ mkHsraObjTyInfo descM ty implIFaces flds =
 mkIFaceTyInfo
   :: Maybe G.Description -> G.NamedType
   -> Map.HashMap G.Name ObjFldInfo -> TypeLoc -> MemberTypes -> IFaceTyInfo
-mkIFaceTyInfo descM ty flds loc =
+mkIFaceTyInfo descM ty flds _ =
   IFaceTyInfo descM ty $ Map.insert (_fiName newFld) newFld flds
   where
     newFld = typenameFld
diff --git a/server/src-lib/Hasura/Prelude.hs b/server/src-lib/Hasura/Prelude.hs
index 55805fb19d049..bbdea55efe15f 100644
--- a/server/src-lib/Hasura/Prelude.hs
+++ b/server/src-lib/Hasura/Prelude.hs
@@ -10,6 +10,7 @@ module Hasura.Prelude
   , afold
   , bsToTxt
   , txtToBs
+  , base64Decode
   , spanMaybeM
   , findWithIndex
   , mapFromL
@@ -62,6 +63,9 @@ import           Test.QuickCheck.Arbitrary.Generic as M
 import           Text.Read                         as M (readEither, readMaybe)
 
 import qualified Data.ByteString                   as B
+import qualified Data.ByteString.Lazy              as BL
+
+import qualified Data.ByteString.Base64.Lazy       as Base64
 import qualified Data.HashMap.Strict               as Map
 import qualified Data.Text                         as T
 import qualified Data.Text.Encoding                as TE
@@ -99,6 +103,11 @@ bsToTxt = TE.decodeUtf8With TE.lenientDecode
 txtToBs :: Text -> B.ByteString
 txtToBs = TE.encodeUtf8
 
+base64Decode :: Text -> BL.ByteString
+base64Decode =
+  Base64.decodeLenient . BL.fromStrict . txtToBs
+
+
 -- Like 'span', but monadic and with a function that produces 'Maybe' instead of 'Bool'
 spanMaybeM
   :: (Foldable f, Monad m)
diff --git a/server/src-lib/Hasura/RQL/DML/Select.hs b/server/src-lib/Hasura/RQL/DML/Select.hs
index e80ca5c9e53ef..2517b5c565d7a 100644
--- a/server/src-lib/Hasura/RQL/DML/Select.hs
+++ b/server/src-lib/Hasura/RQL/DML/Select.hs
@@ -272,13 +272,13 @@ selectP2 jsonAggSelect (sel, p) =
   where
     selectSQL = toSQL $ mkSQLSelect jsonAggSelect sel
 
-selectQuerySQL :: JsonAggSelect -> AnnSimpleSel -> Q.Query
-selectQuerySQL jsonAggSelect sel =
-  Q.fromBuilder $ toSQL $ mkSQLSelect jsonAggSelect sel
+-- selectQuerySQL :: JsonAggSelect -> AnnSimpleSel -> Q.Query
+-- selectQuerySQL jsonAggSelect sel =
+--   Q.fromBuilder $ toSQL $ mkSQLSelect jsonAggSelect sel
 
-selectAggQuerySQL :: AnnAggregateSelect -> Q.Query
-selectAggQuerySQL =
-  Q.fromBuilder . toSQL . mkAggregateSelect
+-- selectAggQuerySQL :: AnnAggregateSelect -> Q.Query
+-- selectAggQuerySQL =
+--   Q.fromBuilder . toSQL . mkAggregateSelect
 
 asSingleRowJsonResp :: Q.Query -> [Q.PrepArg] -> Q.TxE QErr EncJSON
 asSingleRowJsonResp query args =
diff --git a/server/src-lib/Hasura/RQL/DML/Select/Internal.hs b/server/src-lib/Hasura/RQL/DML/Select/Internal.hs
index 9766fc5cf7af2..b64d0f6efecf6 100644
--- a/server/src-lib/Hasura/RQL/DML/Select/Internal.hs
+++ b/server/src-lib/Hasura/RQL/DML/Select/Internal.hs
@@ -727,13 +727,15 @@ processAnnFields sourcePrefix fieldAlias similarArrFields annFields = do
     case field of
       AFExpression t -> pure $ S.SELit t
 
+      AFNodeId tn pKeys -> pure $ mkNodeId tn pKeys
+
       AFColumn c -> toSQLCol c
 
       AFObjectRelation objSel -> withWriteObjectRelation $ do
         let AnnRelationSelectG relName relMapping annSel = objSel
             objRelSourcePrefix = mkObjectRelationTableAlias sourcePrefix relName
         (selectSource, extractors) <- processAnnSimpleSelect (mkSourcePrefixes objRelSourcePrefix)
-                                        fieldName PLSQNotRequired annSel
+                                      fieldName PLSQNotRequired annSel
         let objRelSource = ObjectRelationSource relName relMapping selectSource
         pure ( objRelSource
              , extractors
@@ -796,6 +798,19 @@ processAnnFields sourcePrefix fieldAlias similarArrFields annFields = do
       Nothing                     -> sqlExp
       Just (ColumnOp opText cExp) -> S.mkSQLOpExp opText sqlExp cExp
 
+    mkNodeId :: QualifiedTable -> NonEmpty PGColumnInfo -> S.SQLExp
+    mkNodeId (QualifiedObject tableSchema tableName) pkeyColumns =
+      let tableObjectExp = S.applyJsonBuildObj
+                           [ S.SELit "schema"
+                           , S.SELit (getSchemaTxt tableSchema)
+                           , S.SELit "name"
+                           , S.SELit (toTxt tableName)
+                           ]
+      in encodeBase64 $ flip S.SETyAnn S.textTypeAnn $ S.applyJsonBuildObj
+         [ S.SELit "table", tableObjectExp
+         , S.SELit "columns", mkPrimaryKeyColumnsObjectExp sourcePrefix pkeyColumns
+         ]
+
 injectJoinCond :: S.BoolExp       -- ^ Join condition
                -> S.BoolExp -- ^ Where condition
                -> S.WhereFrag     -- ^ New where frag
@@ -991,6 +1006,22 @@ pageInfoSelectAliasIden = Iden "__page_info"
 cursorsSelectAliasIden :: Iden
 cursorsSelectAliasIden = Iden "__cursors_select"
 
+mkPrimaryKeyColumnsObjectExp :: Iden -> NonEmpty PGColumnInfo -> S.SQLExp
+mkPrimaryKeyColumnsObjectExp sourcePrefix primaryKeyColumns =
+  S.applyJsonBuildObj $ flip concatMap (toList primaryKeyColumns) $
+  \pgColumnInfo ->
+    [ S.SELit $ getPGColTxt $ pgiColumn pgColumnInfo
+    , toJSONableExp False (pgiType pgColumnInfo) False $
+      S.mkQIdenExp (mkBaseTableAlias sourcePrefix) $ pgiColumn pgColumnInfo
+    ]
+
+encodeBase64 :: S.SQLExp -> S.SQLExp
+encodeBase64 t =
+  S.SEFnApp "encode"
+  [S.SEFnApp "convert_to" [t, S.SELit "UTF8"] Nothing, S.SELit "base64"]
+  Nothing
+
+
 processConnectionSelect
   :: ( MonadReader Bool m
      , MonadWriter JoinTree m
@@ -1015,7 +1046,7 @@ processConnectionSelect sourcePrefixes fieldAlias relAlias colMapping connection
         Nothing ->
           -- Extract primary key columns from base select along with cursor expression.
           -- Those columns are required to perform connection split via a WHERE clause.
-          mkCursorExtractor primaryKeyColumnsCursor : primaryKeyColumnExtractors
+          mkCursorExtractor (mkPrimaryKeyColumnsObjectExp thisPrefix primaryKeyColumns) : primaryKeyColumnExtractors
       orderByExp = _ssOrderBy selectSource
   (topExtractorExp, exps) <- flip runStateT [] $ processFields orderByExp
   let topExtractor = S.Extractor topExtractorExp $ Just $ S.Alias fieldIden
@@ -1033,14 +1064,6 @@ processConnectionSelect sourcePrefixes fieldAlias relAlias colMapping connection
     thisPrefix = _pfThis sourcePrefixes
     permLimitSubQuery = PLSQNotRequired
 
-    primaryKeyColumnsCursor =
-      S.applyJsonBuildObj $ flip concatMap (toList primaryKeyColumns) $
-      \pgColumnInfo ->
-        [ S.SELit $ getPGColTxt $ pgiColumn pgColumnInfo
-        , toJSONableExp False (pgiType pgColumnInfo) False $
-          S.mkQIdenExp (mkBaseTableAlias thisPrefix) $ pgiColumn pgColumnInfo
-        ]
-
     primaryKeyColumnExtractors =
       flip map (toList primaryKeyColumns) $
       \pgColumnInfo ->
@@ -1073,10 +1096,6 @@ processConnectionSelect sourcePrefixes fieldAlias relAlias colMapping connection
         EdgeNode annFields ->
           mkSimilarArrayFields annFields $ _saOrderBy tableArgs
 
-    encodeBase64 t = S.SEFnApp "encode"
-                     [S.SETyAnn t $ S.TypeAnn "bytea", S.SELit "base64"]
-                     Nothing
-
     mkSimpleJsonAgg rowExp ob =
       let jsonAggExp = S.SEFnApp "json_agg" [rowExp] ob
       in S.SEFnApp "coalesce" [jsonAggExp, S.SELit "[]"] Nothing
diff --git a/server/src-lib/Hasura/RQL/DML/Select/Types.hs b/server/src-lib/Hasura/RQL/DML/Select/Types.hs
index fc4e6fa1cf81e..b819119007151 100644
--- a/server/src-lib/Hasura/RQL/DML/Select/Types.hs
+++ b/server/src-lib/Hasura/RQL/DML/Select/Types.hs
@@ -175,6 +175,7 @@ data AnnFieldG v
   | AFObjectRelation !(ObjectRelationSelectG v)
   | AFArrayRelation !(ArraySelectG v)
   | AFComputedField !(ComputedFieldSelect v)
+  | AFNodeId !QualifiedTable !(NonEmpty PGColumnInfo)
   | AFExpression !T.Text
   deriving (Show, Eq)
 
@@ -194,6 +195,7 @@ traverseAnnField f = \case
   AFObjectRelation sel -> AFObjectRelation <$> traverse (traverseAnnSimpleSelect f) sel
   AFArrayRelation sel -> AFArrayRelation <$> traverseArraySelect f sel
   AFComputedField sel -> AFComputedField <$> traverseComputedFieldSelect f sel
+  AFNodeId qt pKeys -> pure $ AFNodeId qt pKeys
   AFExpression t -> AFExpression <$> pure t
 
 type AnnField = AnnFieldG S.SQLExp
diff --git a/server/src-lib/Hasura/Server/Utils.hs b/server/src-lib/Hasura/Server/Utils.hs
index d15827233ddc9..d6dfff2474401 100644
--- a/server/src-lib/Hasura/Server/Utils.hs
+++ b/server/src-lib/Hasura/Server/Utils.hs
@@ -11,7 +11,6 @@ import           Language.Haskell.TH.Syntax (Lift, Q, TExp)
 import           System.Environment
 import           System.Exit
 import           System.Process
-import           Data.Aeson.Internal
 
 import qualified Data.ByteString            as B
 import qualified Data.CaseInsensitive       as CI
@@ -29,7 +28,6 @@ import qualified Network.Wreq               as Wreq
 import qualified Text.Regex.TDFA            as TDFA
 import qualified Text.Regex.TDFA.ReadRegex  as TDFA
 import qualified Text.Regex.TDFA.TDFA       as TDFA
-import qualified Data.Vector                as V
 
 import           Hasura.RQL.Instances       ()
 
diff --git a/server/tests-py/queries/graphql_query/basic/select_query_fragment_cycles.yaml b/server/tests-py/queries/graphql_query/basic/select_query_fragment_cycles.yaml
index 3f44e6ba1beec..e66c929083178 100644
--- a/server/tests-py/queries/graphql_query/basic/select_query_fragment_cycles.yaml
+++ b/server/tests-py/queries/graphql_query/basic/select_query_fragment_cycles.yaml
@@ -25,6 +25,6 @@ query:
 response:
   errors:
   - extensions:
-      path: $.selectionSet.author.selectionSet.authorFragment.selectionSet.articles.selectionSet.articleFragment.selectionSet.author.selectionSet.authorFragment
+      path: $.selectionSet.author.selectionSet.authorFragment.selectionSet.articles.selectionSet.articleFragment.selectionSet.author.selectionSet
       code: validation-failed
     message: cannot spread fragment "authorFragment" within itself via articleFragment,authorFragment
diff --git a/server/tests-py/test_schema_stitching.py b/server/tests-py/test_schema_stitching.py
index 642d3148e995f..7bd7985cc7c1c 100644
--- a/server/tests-py/test_schema_stitching.py
+++ b/server/tests-py/test_schema_stitching.py
@@ -364,10 +364,10 @@ def test_remote_query_error(self, ws_client):
         try:
             ev = next(resp)
             print(ev)
-            assert ev['type'] == 'data' and ev['id'] == query_id, ev
+            assert ev['type'] == 'error' and ev['id'] == query_id, ev
             assert 'errors' in ev['payload']
             assert ev['payload']['errors'][0]['message'] == \
-                'Cannot query field "blah" on type "User".'
+                'field "blah" not found in type: \'User\''
         finally:
             ws_client.stop(query_id)
 

From 45cc7fe8ec9b7f0b62b0ea2d06aff429815a8dcf Mon Sep 17 00:00:00 2001
From: Rishichandra Wawhal <rishi@hasura.io>
Date: Tue, 26 May 2020 22:40:14 +0530
Subject: [PATCH 11/29] add relay toggle on graphiql

---
 console/src/Endpoints.js                      |  1 +
 .../components/Common/utils/graphqlUtils.ts   | 10 +++-
 .../Services/ApiExplorer/Actions.js           | 34 +++++++++--
 .../ApiExplorer/Analyzer/AnalyzeButton.js     | 10 ++--
 .../Services/ApiExplorer/ApiExplorer.js       |  5 ++
 .../Services/ApiExplorer/ApiExplorer.scss     |  5 ++
 .../ApiExplorer/ApiRequest/ApiRequest.js      | 35 +++++++++++-
 .../Services/ApiExplorer/ApiRequestWrapper.js |  2 +
 .../GraphiQLWrapper/GraphiQLWrapper.js        | 39 +++++++++----
 .../OneGraphExplorer/OneGraphExplorer.js      | 28 +++++++---
 .../components/Services/ApiExplorer/state.js  | 56 +++++++++----------
 .../components/Services/ApiExplorer/utils.js  |  5 ++
 12 files changed, 169 insertions(+), 61 deletions(-)

diff --git a/console/src/Endpoints.js b/console/src/Endpoints.js
index e6902b4beb580..cfce4f48b5a11 100644
--- a/console/src/Endpoints.js
+++ b/console/src/Endpoints.js
@@ -10,6 +10,7 @@ const Endpoints = {
   getSchema: `${baseUrl}/v1/query`,
   serverConfig: `${baseUrl}/v1alpha1/config`,
   graphQLUrl: `${baseUrl}/v1/graphql`,
+  relayURL: `${baseUrl}/v1/relay`,
   schemaChange: `${baseUrl}/v1/query`,
   query: `${baseUrl}/v1/query`,
   rawSQL: `${baseUrl}/v1/query`,
diff --git a/console/src/components/Common/utils/graphqlUtils.ts b/console/src/components/Common/utils/graphqlUtils.ts
index d7591291dfb3a..b980febd4a41a 100644
--- a/console/src/components/Common/utils/graphqlUtils.ts
+++ b/console/src/components/Common/utils/graphqlUtils.ts
@@ -6,6 +6,14 @@ import {
 import React from 'react';
 import endpoints from '../../../Endpoints';
 
+export const getGraphQLQueryPayload = (
+  query: string,
+  variables: Record<string, any>
+) => ({
+  query,
+  variables,
+});
+
 export const useIntrospectionSchema = (headers = {}) => {
   const [schema, setSchema] = React.useState<GraphQLSchema | null>(null);
   const [loading, setLoading] = React.useState(true);
@@ -17,7 +25,7 @@ export const useIntrospectionSchema = (headers = {}) => {
     fetch(endpoints.graphQLUrl, {
       method: 'POST',
       headers,
-      body: JSON.stringify({ query: getIntrospectionQuery() }),
+      body: JSON.stringify(getGraphQLQueryPayload(getIntrospectionQuery(), {})),
     })
       .then(r => r.json())
       .then(response => {
diff --git a/console/src/components/Services/ApiExplorer/Actions.js b/console/src/components/Services/ApiExplorer/Actions.js
index f8e5dd01e762f..8bbb0998657c6 100644
--- a/console/src/components/Services/ApiExplorer/Actions.js
+++ b/console/src/components/Services/ApiExplorer/Actions.js
@@ -9,7 +9,7 @@ import { WebSocketLink } from 'apollo-link-ws';
 import { parse } from 'graphql';
 import { execute } from 'apollo-link';
 
-import { getHeadersAsJSON } from './utils';
+import { getHeadersAsJSON, getGraphQLEndpoint } from './utils';
 import { saveAppState, clearState } from '../../AppState.js';
 import { ADMIN_SECRET_HEADER_KEY } from '../../../constants';
 
@@ -44,6 +44,18 @@ const CREATE_WEBSOCKET_CLIENT = 'ApiExplorer/CREATE_WEBSOCKET_CLIENT';
 const FOCUS_ROLE_HEADER = 'ApiExplorer/FOCUS_ROLE_HEADER';
 const UNFOCUS_ROLE_HEADER = 'ApiExplorer/UNFOCUS_ROLE_HEADER';
 
+const LOADING = 'ApiExplorer/LOADING';
+export const setLoading = isLoading => ({
+  type: LOADING,
+  data: isLoading,
+});
+
+const SWITCH_GRAPHIQL_MODE = 'ApiExplorer/SWITCH_GRAPHIQL_MODE';
+export const switchGraphiQLMode = mode => ({
+  type: SWITCH_GRAPHIQL_MODE,
+  mode,
+});
+
 const clearHistory = () => {
   return {
     type: CLEAR_HISTORY,
@@ -88,8 +100,9 @@ const getChangedHeaders = (headers, changedHeaderDetails) => {
   return nonEmptyHeaders;
 };
 
-const verifyJWTToken = token => dispatch => {
-  const url = Endpoints.graphQLUrl;
+const verifyJWTToken = token => (dispatch, getState) => {
+  const { mode: graphiqlMode } = getState().apiexplorer;
+  const url = getGraphQLEndpoint(graphiqlMode);
   const body = {
     query: '{ __type(name: "dummy") {name}}',
     variables: null,
@@ -199,10 +212,11 @@ const graphQLFetcherFinal = (graphQLParams, url, headers) => {
 };
 
 /* Analyse Fetcher */
-const analyzeFetcher = (url, headers) => {
+const analyzeFetcher = (headers, mode) => {
   return query => {
     const editedQuery = {
       query,
+      is_relay: mode === 'relay',
     };
 
     const user = {
@@ -227,7 +241,7 @@ const analyzeFetcher = (url, headers) => {
 
     editedQuery.user = user;
 
-    return fetch(`${url}/explain`, {
+    return fetch(`${Endpoints.graphQLUrl}/explain`, {
       method: 'post',
       headers: reqHeaders,
       body: JSON.stringify(editedQuery),
@@ -616,6 +630,16 @@ const apiExplorerReducer = (state = defaultState, action) => {
           },
         },
       };
+    case SWITCH_GRAPHIQL_MODE:
+      return {
+        ...state,
+        mode: action.mode,
+      };
+    case LOADING:
+      return {
+        ...state,
+        loading: action.data,
+      };
     default:
       return state;
   }
diff --git a/console/src/components/Services/ApiExplorer/Analyzer/AnalyzeButton.js b/console/src/components/Services/ApiExplorer/Analyzer/AnalyzeButton.js
index 99acffa306cee..e1d76e42428dd 100644
--- a/console/src/components/Services/ApiExplorer/Analyzer/AnalyzeButton.js
+++ b/console/src/components/Services/ApiExplorer/Analyzer/AnalyzeButton.js
@@ -4,6 +4,7 @@ import QueryAnalyzer from './QueryAnalyzer';
 import GraphiQL from 'graphiql';
 import { print, parse } from 'graphql';
 import { isValidGraphQLOperation } from '../utils';
+import { getGraphQLQueryPayload } from '../../../Common/utils/graphqlUtils';
 
 export default class AnalyseButton extends React.Component {
   constructor(props) {
@@ -20,7 +21,7 @@ export default class AnalyseButton extends React.Component {
     };
   }
   render() {
-    const operations = this.props.operations;
+    const { operations, mode } = this.props;
     const optionsOpen = this.state.optionsOpen;
     const hasOptions = operations && operations.length > 1;
 
@@ -67,6 +68,7 @@ export default class AnalyseButton extends React.Component {
         {this.state.analyseQuery && (
           <QueryAnalyzer
             show={this.state.isAnalysing}
+            mode={mode}
             analyseQuery={this.state.analyseQuery}
             clearAnalyse={this.clearAnalyse.bind(this)}
             {...this.props}
@@ -125,15 +127,13 @@ export default class AnalyseButton extends React.Component {
     }
 
     const plainQuery = print(parseQuery);
-    const query = {
-      query: plainQuery,
-      variables: jsonVariables,
-    };
+    const query = getGraphQLQueryPayload(plainQuery, jsonVariables);
     if (operation) {
       query.operationName = operation;
     }
     const analyseQuery = {
       query,
+      is_relay: this.props.mode === 'relay',
     };
     this.setState({
       analyseQuery,
diff --git a/console/src/components/Services/ApiExplorer/ApiExplorer.js b/console/src/components/Services/ApiExplorer/ApiExplorer.js
index 1b0f18d7dd407..109d842e9775b 100644
--- a/console/src/components/Services/ApiExplorer/ApiExplorer.js
+++ b/console/src/components/Services/ApiExplorer/ApiExplorer.js
@@ -63,6 +63,8 @@ class ApiExplorer extends Component {
       location,
       serverVersion,
       serverConfig,
+      mode,
+      loading,
     } = this.props;
 
     const styles = require('./ApiExplorer.scss');
@@ -83,12 +85,14 @@ class ApiExplorer extends Component {
             details={displayedApi.details}
             request={displayedApi.request}
             route={route}
+            mode={mode}
             dataHeaders={dataHeaders}
             numberOfTables={tables.length}
             headerFocus={headerFocus}
             urlParams={location.query}
             serverVersion={serverVersion}
             consoleUrl={consoleUrl}
+            loading={loading}
             serverConfig={serverConfig}
           />
         </div>
@@ -105,6 +109,7 @@ ApiExplorer.propTypes = {
   tables: PropTypes.array.isRequired,
   headerFocus: PropTypes.bool.isRequired,
   location: PropTypes.object.isRequired,
+  mode: PropTypes.string.isRequired,
 };
 
 const generatedApiExplorer = connect => {
diff --git a/console/src/components/Services/ApiExplorer/ApiExplorer.scss b/console/src/components/Services/ApiExplorer/ApiExplorer.scss
index 9c815fb5f4ef7..912442f4129e7 100644
--- a/console/src/components/Services/ApiExplorer/ApiExplorer.scss
+++ b/console/src/components/Services/ApiExplorer/ApiExplorer.scss
@@ -827,3 +827,8 @@ label {
     }
   }
 }
+
+.graphiqlModeToggle {
+  margin-top: -10px;
+  float: right;
+}
\ No newline at end of file
diff --git a/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js b/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js
index d52404aa7b542..2b60f9ef33849 100644
--- a/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js
+++ b/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js
@@ -1,12 +1,12 @@
 import React, { Component } from 'react';
 import PropTypes from 'prop-types';
-
 import jwt from 'jsonwebtoken';
 
 import TextAreaWithCopy from '../../../Common/TextAreaWithCopy/TextAreaWithCopy';
 import OverlayTrigger from 'react-bootstrap/lib/OverlayTrigger';
 import Tooltip from 'react-bootstrap/lib/Tooltip';
 import Modal from '../../../Common/Modal/Modal';
+import TooltipCustom from '../../../Common/Tooltip/Tooltip';
 
 import {
   changeRequestHeader,
@@ -15,9 +15,11 @@ import {
   unfocusTypingHeader,
   verifyJWTToken,
   setHeadersBulk,
+  switchGraphiQLMode,
 } from '../Actions';
 
 import GraphiQLWrapper from '../GraphiQLWrapper/GraphiQLWrapper';
+import Toggle from '../../../Common/Toggle/Toggle';
 
 import CollapsibleToggle from '../../../Common/CollapsibleToggle/CollapsibleToggle';
 
@@ -35,6 +37,7 @@ import {
   persistAdminSecretHeaderWasAdded,
   removePersistedAdminSecretHeaderWasAdded,
 } from './utils';
+import { getGraphQLEndpoint } from '../utils';
 
 import styles from '../ApiExplorer.scss';
 import { ADMIN_SECRET_HEADER_KEY } from '../../../../constants';
@@ -207,6 +210,7 @@ class ApiRequest extends Component {
   }
 
   render() {
+    const { mode, dispatch, loading } = this.props;
     const { isAnalyzingToken, tokenInfo, analyzingHeaderRow } = this.state;
 
     const { is_jwt_set: isJWTSet = false } = this.props.serverConfig;
@@ -227,6 +231,11 @@ class ApiRequest extends Component {
         this.setState({ endpointSectionIsOpen: newIsOpen });
       };
 
+      const toggleGraphiqlMode = () => {
+        if (loading) return;
+        dispatch(switchGraphiQLMode(mode === 'relay' ? 'graphql' : 'relay'));
+      };
+
       return (
         <CollapsibleToggle
           title={'GraphQL Endpoint'}
@@ -259,8 +268,7 @@ class ApiRequest extends Component {
                   </button>
                 </div>
                 <input
-                  onChange={this.onUrlChanged}
-                  value={this.props.url || ''}
+                  value={getGraphQLEndpoint(mode)}
                   type="text"
                   readOnly
                   className={styles.inputGroupInput + ' form-control '}
@@ -268,6 +276,26 @@ class ApiRequest extends Component {
               </div>
             </div>
             <div className={styles.stickySeparator} />
+            <div
+              className={`${styles.display_flex} ${styles.graphiqlModeToggle} ${styles.cursorPointer}`}
+              onClick={toggleGraphiqlMode}
+            >
+              <Toggle
+                checked={mode === 'relay'}
+                className={`${styles.display_flex} ${styles.add_mar_right_mid}`}
+                readOnly
+                disabled={loading}
+                icons={false}
+              />
+              <span className={styles.add_mar_right_mid}>Relay API</span>
+              <TooltipCustom
+                id="relay-mode-toggle"
+                placement="left"
+                message={
+                  'Toggle to point this GraphiQL to a relay-compliant GraphQL API served at /v1/relay'
+                }
+              />
+            </div>
           </div>
         </CollapsibleToggle>
       );
@@ -564,6 +592,7 @@ class ApiRequest extends Component {
           return (
             <div className={styles.apiRequestBody}>
               <GraphiQLWrapper
+                mode={mode}
                 data={this.props}
                 numberOfTables={this.props.numberOfTables}
                 dispatch={this.props.dispatch}
diff --git a/console/src/components/Services/ApiExplorer/ApiRequestWrapper.js b/console/src/components/Services/ApiExplorer/ApiRequestWrapper.js
index 742d5d0aa5109..5d5aeef4ba1b6 100644
--- a/console/src/components/Services/ApiExplorer/ApiRequestWrapper.js
+++ b/console/src/components/Services/ApiExplorer/ApiRequestWrapper.js
@@ -58,6 +58,7 @@ class ApiRequestWrapper extends Component {
             this.props.request.bodyType ? this.props.request.bodyType : ''
           }
           credentials={this.props.credentials}
+          mode={this.props.mode}
           method={this.props.request.method}
           url={this.props.request.url}
           headers={this.props.request.headers}
@@ -65,6 +66,7 @@ class ApiRequestWrapper extends Component {
           params={this.props.request.params}
           explorerData={this.props.explorerData}
           dispatch={this.props.dispatch}
+          loading={this.props.loading}
           dataHeaders={this.props.dataHeaders}
           numberOfTables={this.props.numberOfTables}
           headerFocus={this.props.headerFocus}
diff --git a/console/src/components/Services/ApiExplorer/GraphiQLWrapper/GraphiQLWrapper.js b/console/src/components/Services/ApiExplorer/GraphiQLWrapper/GraphiQLWrapper.js
index 5cd5986c19ee0..51f91961ecae4 100644
--- a/console/src/components/Services/ApiExplorer/GraphiQLWrapper/GraphiQLWrapper.js
+++ b/console/src/components/Services/ApiExplorer/GraphiQLWrapper/GraphiQLWrapper.js
@@ -1,6 +1,7 @@
 import React, { Component } from 'react';
 import { push } from 'react-router-redux';
 import GraphiQL from 'graphiql';
+import { connect } from 'react-redux';
 import PropTypes from 'prop-types';
 import GraphiQLErrorBoundary from './GraphiQLErrorBoundary';
 import OneGraphExplorer from '../OneGraphExplorer/OneGraphExplorer';
@@ -26,6 +27,7 @@ import {
   setTypeDefinition,
   setDerivedActionParentOperation,
 } from '../../Actions/Add/reducer';
+import { getGraphQLEndpoint } from '../utils';
 
 import 'graphiql/graphiql.css';
 import './GraphiQL.css';
@@ -52,7 +54,14 @@ class GraphiQLWrapper extends Component {
   render() {
     const styles = require('../../../Common/Common.scss');
 
-    const { numberOfTables, urlParams, headerFocus, dispatch } = this.props;
+    const {
+      numberOfTables,
+      urlParams,
+      headerFocus,
+      dispatch,
+      mode,
+      loading,
+    } = this.props;
     const graphqlNetworkData = this.props.data;
     const graphQLFetcher = graphQLParams => {
       if (headerFocus) {
@@ -61,14 +70,14 @@ class GraphiQLWrapper extends Component {
 
       return graphQLFetcherFinal(
         graphQLParams,
-        graphqlNetworkData.url,
+        getGraphQLEndpoint(mode),
         graphqlNetworkData.headers
       );
     };
 
     const analyzeFetcherInstance = analyzeFetcher(
-      graphqlNetworkData.url,
-      graphqlNetworkData.headers
+      graphqlNetworkData.headers,
+      mode
     );
 
     let graphiqlContext;
@@ -170,12 +179,14 @@ class GraphiQLWrapper extends Component {
             onClick: () => window.open(voyagerUrl, '_blank'),
             icon: <i className="fa fa-external-link" aria-hidden="true" />,
           },
-          {
+        ];
+        if (mode === 'graphql') {
+          buttons.push({
             label: 'Derive action',
             title: 'Derive action for the given mutation',
             onClick: deriveActionFromOperation,
-          },
-        ];
+          });
+        }
         return buttons.map(b => {
           return <GraphiQL.Button key={b.label} {...b} />;
         });
@@ -183,12 +194,12 @@ class GraphiQLWrapper extends Component {
 
       return (
         <GraphiQL
+          {...graphiqlProps}
           ref={c => {
             graphiqlContext = c;
           }}
           fetcher={graphQLFetcher}
           voyagerUrl={voyagerUrl}
-          {...graphiqlProps}
         >
           <GraphiQL.Logo>GraphiQL</GraphiQL.Logo>
           <GraphiQL.Toolbar>
@@ -210,13 +221,16 @@ class GraphiQLWrapper extends Component {
         >
           <OneGraphExplorer
             renderGraphiql={renderGraphiql}
-            endpoint={graphqlNetworkData.url}
+            endpoint={getGraphQLEndpoint(mode)}
+            dispatch={dispatch}
             headers={graphqlNetworkData.headers}
             headersInitialised={graphqlNetworkData.headersInitialised}
             headerFocus={headerFocus}
             urlParams={urlParams}
+            loading={loading}
             numberOfTables={numberOfTables}
             dispatch={dispatch}
+            mode={mode}
           />
         </div>
       </GraphiQLErrorBoundary>
@@ -232,4 +246,9 @@ GraphiQLWrapper.propTypes = {
   urlParams: PropTypes.object.isRequired,
 };
 
-export default GraphiQLWrapper;
+const mapStateToProps = state => ({
+  mode: state.apiexplorer.mode,
+  loading: state.apiexplorer.loading,
+});
+
+export default connect(mapStateToProps)(GraphiQLWrapper);
diff --git a/console/src/components/Services/ApiExplorer/OneGraphExplorer/OneGraphExplorer.js b/console/src/components/Services/ApiExplorer/OneGraphExplorer/OneGraphExplorer.js
index 760f9ce038846..6f48ec6715a68 100644
--- a/console/src/components/Services/ApiExplorer/OneGraphExplorer/OneGraphExplorer.js
+++ b/console/src/components/Services/ApiExplorer/OneGraphExplorer/OneGraphExplorer.js
@@ -1,6 +1,7 @@
 import React from 'react';
 import { getIntrospectionQuery, buildClientSchema } from 'graphql';
 import GraphiQLExplorer from 'graphiql-explorer';
+import { setLoading } from '../Actions';
 
 import {
   makeDefaultArg,
@@ -25,7 +26,6 @@ class OneGraphExplorer extends React.Component {
     schema: null,
     query: undefined,
     isResizing: false,
-    loading: false,
     previousIntrospectionHeaders: [],
   };
 
@@ -34,9 +34,14 @@ class OneGraphExplorer extends React.Component {
     this.introspect();
   }
 
-  componentDidUpdate() {
-    const { headerFocus, headers } = this.props;
-    const { loading, previousIntrospectionHeaders } = this.state;
+  componentDidUpdate(prevProps) {
+    const { headerFocus, headers, loading } = this.props;
+    const { previousIntrospectionHeaders } = this.state;
+    // always introspect if mode changes
+    if (this.props.mode !== prevProps.mode) {
+      this.introspect();
+      return;
+    }
     if (!headerFocus && !loading) {
       if (
         JSON.stringify(headers) !== JSON.stringify(previousIntrospectionHeaders)
@@ -78,12 +83,18 @@ class OneGraphExplorer extends React.Component {
   }
 
   introspect() {
-    const { endpoint, headersInitialised, headers: headers_ } = this.props;
+    const {
+      endpoint,
+      headersInitialised,
+      headers: headers_,
+      dispatch,
+    } = this.props;
     if (!headersInitialised) {
       return;
     }
     const headers = JSON.parse(JSON.stringify(headers_));
-    this.setState({ loading: true });
+    dispatch(setLoading(true));
+    this.setState({ schema: null });
     fetch(endpoint, {
       method: 'POST',
       headers: getHeadersAsJSON(headers || []),
@@ -95,16 +106,17 @@ class OneGraphExplorer extends React.Component {
       .then(result => {
         this.setState({
           schema: buildClientSchema(result.data),
-          loading: false,
           previousIntrospectionHeaders: headers,
         });
       })
       .catch(() => {
         this.setState({
           schema: null,
-          loading: false,
           previousIntrospectionHeaders: headers,
         });
+      })
+      .finally(() => {
+        dispatch(setLoading(false));
       });
   }
 
diff --git a/console/src/components/Services/ApiExplorer/state.js b/console/src/components/Services/ApiExplorer/state.js
index 5b7240127a98b..69ad1e9a35a43 100644
--- a/console/src/components/Services/ApiExplorer/state.js
+++ b/console/src/components/Services/ApiExplorer/state.js
@@ -1,4 +1,4 @@
-import globals from '../../../Globals';
+import endpoints from '../../../Endpoints';
 
 const defaultHeader = [
   {
@@ -8,37 +8,33 @@ const defaultHeader = [
     isNewHeader: false,
     isDisabled: true,
   },
+  {
+    key: '',
+    value: '',
+    isActive: false,
+    isNewHeader: true,
+  },
 ];
-defaultHeader.push({
-  key: '',
-  value: '',
-  isActive: false,
-  isNewHeader: true,
-});
-
-const getUrl = path => {
-  return `${globals.dataApiUrl}${path}`;
-};
 
-const dataApisContent = [];
-// check project version
-dataApisContent.push({
-  id: 'DataApi-3',
-  details: {
-    title: 'GraphQL API',
-    description:
-      'GraphQL API for CRUD operations on tables & views in your database',
-    category: 'data',
-  },
-  request: {
-    method: 'POST',
-    url: getUrl('/v1/graphql'),
-    headers: defaultHeader,
-    headersInitialised: false,
-    bodyType: 'graphql',
-    params: JSON.stringify({}, null, 4),
+const dataApisContent = [
+  {
+    id: 'DataApi-3',
+    details: {
+      title: 'GraphQL API',
+      description:
+        'GraphQL API for CRUD operations on tables & views in your database',
+      category: 'data',
+    },
+    request: {
+      method: 'POST',
+      url: endpoints.graphQLUrl,
+      headers: defaultHeader,
+      headersInitialised: false,
+      bodyType: 'graphql',
+      params: JSON.stringify({}, null, 4),
+    },
   },
-});
+];
 
 const dataApis = {
   title: 'Data',
@@ -64,6 +60,8 @@ const defaultState = {
   explorerData,
   authApiExpanded: 'Username-password Login',
   headerFocus: false,
+  mode: 'graphql',
+  loading: false,
 };
 
 export default defaultState;
diff --git a/console/src/components/Services/ApiExplorer/utils.js b/console/src/components/Services/ApiExplorer/utils.js
index 3ed44f2e5f52b..53e5949429792 100644
--- a/console/src/components/Services/ApiExplorer/utils.js
+++ b/console/src/components/Services/ApiExplorer/utils.js
@@ -1,3 +1,5 @@
+import endpoints from '../../../Endpoints';
+
 export const getHeadersAsJSON = (headers = []) => {
   const headerJSON = {};
   const nonEmptyHeaders = headers.filter(header => {
@@ -16,3 +18,6 @@ export const isValidGraphQLOperation = operation => {
     operation.name && operation.name.value && operation.operation === 'query'
   );
 };
+
+export const getGraphQLEndpoint = mode =>
+  mode === 'relay' ? endpoints.relayURL : endpoints.graphQLUrl;

From 44843e6a05bbaa2acfbf0853d97a546660c4ec84 Mon Sep 17 00:00:00 2001
From: rakeshkky <12475069+rakeshkky@users.noreply.github.com>
Date: Wed, 27 May 2020 14:31:55 +0530
Subject: [PATCH 12/29] fix explain api response & index plan id with query
 type

---
 server/src-lib/Hasura/GraphQL/Execute.hs      | 30 ++++++++-----------
 server/src-lib/Hasura/GraphQL/Execute/Plan.hs | 16 +++++-----
 .../src-lib/Hasura/GraphQL/Execute/Query.hs   | 15 +++++++++-
 server/src-lib/Hasura/GraphQL/Explain.hs      |  9 +++---
 .../src-lib/Hasura/GraphQL/Transport/HTTP.hs  | 14 ++++-----
 .../Hasura/GraphQL/Transport/WebSocket.hs     | 20 ++++++-------
 server/src-lib/Hasura/Server/App.hs           | 12 ++++----
 7 files changed, 63 insertions(+), 53 deletions(-)

diff --git a/server/src-lib/Hasura/GraphQL/Execute.hs b/server/src-lib/Hasura/GraphQL/Execute.hs
index 8e1bdb9e1644f..10d786e623e58 100644
--- a/server/src-lib/Hasura/GraphQL/Execute.hs
+++ b/server/src-lib/Hasura/GraphQL/Execute.hs
@@ -1,6 +1,6 @@
 module Hasura.GraphQL.Execute
   ( GQExecPlan(..)
-  , GraphQLAPIType(..)
+  , EQ.GraphQLQueryType(..)
 
   , ExecPlanPartial
   , getExecPlanPartial
@@ -61,12 +61,6 @@ import qualified Hasura.GraphQL.Validate.Types          as VT
 import qualified Hasura.Logging                         as L
 import qualified Hasura.Server.Telemetry.Counters       as Telem
 
--- The GraphQL API type
-data GraphQLAPIType
-  = GATGeneral
-  | GATRelay
-  deriving (Show, Eq)
-
 -- The current execution plan of a graphql operation, it is
 -- currently, either local pg execution or a remote execution
 --
@@ -130,19 +124,19 @@ getExecPlanPartial
   :: (MonadReusability m, MonadError QErr m)
   => UserInfo
   -> SchemaCache
-  -> GraphQLAPIType
+  -> EQ.GraphQLQueryType
   -> Bool
   -> GQLReqParsed
   -> m ExecPlanPartial
-getExecPlanPartial userInfo sc apiType enableAL req = do
+getExecPlanPartial userInfo sc queryType enableAL req = do
 
   -- check if query is in allowlist
   when enableAL checkQueryInAllowlist
 
-  let gCtx = case apiType of
-        GATGeneral -> getGCtx (_uiBackendOnlyFieldAccess userInfo) sc roleName
-        GATRelay   -> maybe GC.emptyGCtx _rctxDefault $
-                      Map.lookup roleName (scRelayGCtxMap sc)
+  let gCtx = case queryType of
+        EQ.QueryHasura -> getGCtx (_uiBackendOnlyFieldAccess userInfo) sc roleName
+        EQ.QueryRelay  -> maybe GC.emptyGCtx _rctxDefault $
+                          Map.lookup roleName (scRelayGCtxMap sc)
 
   queryParts <- flip runReaderT gCtx $ VQ.getQueryParts req
 
@@ -198,15 +192,15 @@ getResolvedExecPlan
   -> Bool
   -> SchemaCache
   -> SchemaCacheVer
-  -> GraphQLAPIType
+  -> EQ.GraphQLQueryType
   -> HTTP.Manager
   -> [N.Header]
   -> GQLReqUnparsed
   -> m (Telem.CacheHit, ExecPlanResolved)
 getResolvedExecPlan pgExecCtx planCache userInfo sqlGenCtx
-  enableAL sc scVer apiType httpManager reqHeaders reqUnparsed = do
+  enableAL sc scVer queryType httpManager reqHeaders reqUnparsed = do
   planM <- liftIO $ EP.getPlan scVer (_uiRole userInfo)
-           opNameM queryStr planCache
+           opNameM queryStr queryType planCache
   let usrVars = _uiSession userInfo
   case planM of
     -- plans are only for queries and subscriptions
@@ -221,11 +215,11 @@ getResolvedExecPlan pgExecCtx planCache userInfo sqlGenCtx
     GQLReq opNameM queryStr queryVars = reqUnparsed
     addPlanToCache plan =
       liftIO $ EP.addPlan scVer (_uiRole userInfo)
-      opNameM queryStr plan planCache
+      opNameM queryStr plan queryType planCache
     noExistingPlan = do
       req <- toParsed reqUnparsed
       (partialExecPlan, queryReusability) <- runReusabilityT $
-        getExecPlanPartial userInfo sc apiType enableAL req
+        getExecPlanPartial userInfo sc queryType enableAL req
       forM partialExecPlan $ \(gCtx, rootSelSet) ->
         case rootSelSet of
           VQ.RMutation selSet -> do
diff --git a/server/src-lib/Hasura/GraphQL/Execute/Plan.hs b/server/src-lib/Hasura/GraphQL/Execute/Plan.hs
index 8482d893ea936..6e012e5884b38 100644
--- a/server/src-lib/Hasura/GraphQL/Execute/Plan.hs
+++ b/server/src-lib/Hasura/GraphQL/Execute/Plan.hs
@@ -28,17 +28,19 @@ data PlanId
   , _piRole               :: !RoleName
   , _piOperationName      :: !(Maybe GH.OperationName)
   , _piQuery              :: !GH.GQLQueryText
+  , _piQueryType          :: !EQ.GraphQLQueryType
   } deriving (Show, Eq, Ord, Generic)
 
 instance Hashable PlanId
 
 instance J.ToJSON PlanId where
-  toJSON (PlanId scVer rn opNameM query) =
+  toJSON (PlanId scVer rn opNameM query queryType) =
     J.object
     [ "schema_cache_version" J..= scVer
     , "role" J..= rn
     , "operation" J..= opNameM
     , "query" J..= query
+    , "query_type" J..= queryType
     ]
 
 newtype PlanCache
@@ -64,19 +66,19 @@ initPlanCache options =
 
 getPlan
   :: SchemaCacheVer -> RoleName -> Maybe GH.OperationName -> GH.GQLQueryText
-  -> PlanCache -> IO (Maybe ReusablePlan)
-getPlan schemaVer rn opNameM q (PlanCache planCache) =
+  -> EQ.GraphQLQueryType -> PlanCache -> IO (Maybe ReusablePlan)
+getPlan schemaVer rn opNameM q queryType (PlanCache planCache) =
   Cache.lookup planId planCache
   where
-    planId = PlanId schemaVer rn opNameM q
+    planId = PlanId schemaVer rn opNameM q queryType
 
 addPlan
   :: SchemaCacheVer -> RoleName -> Maybe GH.OperationName -> GH.GQLQueryText
-  -> ReusablePlan -> PlanCache -> IO ()
-addPlan schemaVer rn opNameM q queryPlan (PlanCache planCache) =
+  -> ReusablePlan -> EQ.GraphQLQueryType -> PlanCache -> IO ()
+addPlan schemaVer rn opNameM q queryPlan queryType (PlanCache planCache) =
   Cache.insert planId queryPlan planCache
   where
-    planId = PlanId schemaVer rn opNameM q
+    planId = PlanId schemaVer rn opNameM q queryType
 
 clearPlanCache :: PlanCache -> IO ()
 clearPlanCache (PlanCache planCache) =
diff --git a/server/src-lib/Hasura/GraphQL/Execute/Query.hs b/server/src-lib/Hasura/GraphQL/Execute/Query.hs
index 44be5135ce9e1..d035f6446f7f6 100644
--- a/server/src-lib/Hasura/GraphQL/Execute/Query.hs
+++ b/server/src-lib/Hasura/GraphQL/Execute/Query.hs
@@ -4,6 +4,7 @@ module Hasura.GraphQL.Execute.Query
   , ReusableQueryPlan
   , GeneratedSqlMap
   , PreparedSql(..)
+  , GraphQLQueryType(..)
   ) where
 
 import qualified Data.Aeson                             as J
@@ -197,7 +198,7 @@ convertQuerySelSet
 convertQuerySelSet initialReusability selSet actionRunner = do
   usrVars <- asks (_uiSession . getter)
   (fldPlans, finalReusability) <- runReusabilityTWith initialReusability $
-    fmap (map (\(a, b) -> (G.Alias $ G.Name a, b))) $ V.traverseObjectSelectionSet selSet $ \fld -> do
+    fmap (map (\(a, b) -> (G.Alias $ G.Name a, b))) $ V.traverseObjectSelectionSet selSet $ \fld ->
       case V._fName fld of
         "__type"     -> fldPlanFromJ <$> R.typeR fld
         "__schema"   -> fldPlanFromJ <$> R.schemaR fld
@@ -274,3 +275,15 @@ mkGeneratedSqlMap resolved =
                 RRRaw _  -> Nothing
                 RRSql ps -> Just ps
     in (alias, res)
+
+-- The GraphQL Query type
+data GraphQLQueryType
+  = QueryHasura
+  | QueryRelay
+  deriving (Show, Eq, Ord, Generic)
+instance Hashable GraphQLQueryType
+
+instance J.ToJSON GraphQLQueryType where
+  toJSON = \case
+    QueryHasura -> "hasura"
+    QueryRelay  -> "relay"
diff --git a/server/src-lib/Hasura/GraphQL/Explain.hs b/server/src-lib/Hasura/GraphQL/Explain.hs
index 81508ce94ca19..175325cd5fe41 100644
--- a/server/src-lib/Hasura/GraphQL/Explain.hs
+++ b/server/src-lib/Hasura/GraphQL/Explain.hs
@@ -37,7 +37,7 @@ data GQLExplain
   , _gqeIsRelay :: !(Maybe Bool)
   } deriving (Show, Eq)
 
-$(J.deriveJSON (J.aesonDrop 4 J.camelCase){J.omitNothingFields=True}
+$(J.deriveJSON (J.aesonDrop 4 J.snakeCase){J.omitNothingFields=True}
   ''GQLExplain
  )
 
@@ -127,7 +127,7 @@ explainGQLQuery
 explainGQLQuery pgExecCtx sc sqlGenCtx enableAL actionExecuter (GQLExplain query userVarsRaw maybeIsRelay) = do
   userInfo <- mkUserInfo UAdminSecretSent sessionVariables $ Just adminRoleName
   (execPlan, queryReusability) <- runReusabilityT $
-    E.getExecPlanPartial userInfo sc apiType enableAL query
+    E.getExecPlanPartial userInfo sc queryType enableAL query
   (gCtx, rootSelSet) <- case execPlan of
     E.GExPHasura (gCtx, rootSelSet) ->
       return (gCtx, rootSelSet)
@@ -135,7 +135,8 @@ explainGQLQuery pgExecCtx sc sqlGenCtx enableAL actionExecuter (GQLExplain query
       throw400 InvalidParams "only hasura queries can be explained"
   case rootSelSet of
     GV.RQuery selSet ->
-      runInTx $ encJFromJValue <$> GV.traverseObjectSelectionSet selSet (explainField userInfo gCtx sqlGenCtx actionExecuter)
+      runInTx $ encJFromJValue . map snd <$>
+        GV.traverseObjectSelectionSet selSet (explainField userInfo gCtx sqlGenCtx actionExecuter)
     GV.RMutation _ ->
       throw400 InvalidParams "only queries can be explained"
     GV.RSubscription fields -> do
@@ -143,6 +144,6 @@ explainGQLQuery pgExecCtx sc sqlGenCtx enableAL actionExecuter (GQLExplain query
                      queryReusability actionExecuter fields
       runInTx $ encJFromJValue <$> E.explainLiveQueryPlan plan
   where
-    apiType = bool E.GATGeneral E.GATRelay $ fromMaybe False maybeIsRelay
+    queryType = bool E.QueryHasura E.QueryRelay $ fromMaybe False maybeIsRelay
     sessionVariables = mkSessionVariablesText $ maybe [] Map.toList userVarsRaw
     runInTx = liftEither <=< liftIO . runExceptT . runLazyTx pgExecCtx Q.ReadOnly
diff --git a/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs b/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs
index 9f18f6e55582f..71e1b995cbb74 100644
--- a/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs
+++ b/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs
@@ -33,16 +33,16 @@ runGQ
   => RequestId
   -> UserInfo
   -> [N.Header]
-  -> E.GraphQLAPIType
+  -> E.GraphQLQueryType
   -> GQLReq GQLQueryText
   -> m (HttpResponse EncJSON)
-runGQ reqId userInfo reqHdrs apiType req = do
+runGQ reqId userInfo reqHdrs queryType req = do
   -- The response and misc telemetry data:
   let telemTransport = Telem.HTTP
   (telemTimeTot_DT, (telemCacheHit, telemLocality, (telemTimeIO_DT, telemQueryType, !resp))) <- withElapsedTime $ do
     E.ExecutionCtx _ sqlGenCtx pgExecCtx planCache sc scVer httpManager enableAL <- ask
     (telemCacheHit, execPlan) <- E.getResolvedExecPlan pgExecCtx planCache
-                                 userInfo sqlGenCtx enableAL sc scVer apiType httpManager reqHdrs req
+                                 userInfo sqlGenCtx enableAL sc scVer queryType httpManager reqHdrs req
     case execPlan of
       E.GExPHasura resolvedOp -> do
         (telemTimeIO, telemQueryType, respHdrs, resp) <- runHasuraGQ reqId req userInfo resolvedOp
@@ -74,13 +74,13 @@ runGQBatched
   -> ResponseInternalErrorsConfig
   -> UserInfo
   -> [N.Header]
-  -> E.GraphQLAPIType
+  -> E.GraphQLQueryType
   -> GQLBatchedReqs GQLQueryText
   -> m (HttpResponse EncJSON)
-runGQBatched reqId responseErrorsConfig userInfo reqHdrs apiType reqs =
+runGQBatched reqId responseErrorsConfig userInfo reqHdrs queryType reqs =
   case reqs of
     GQLSingleRequest req ->
-      runGQ reqId userInfo reqHdrs apiType req
+      runGQ reqId userInfo reqHdrs queryType req
     GQLBatchedReqs batch -> do
       -- It's unclear what we should do if we receive multiple
       -- responses with distinct headers, so just do the simplest thing
@@ -91,7 +91,7 @@ runGQBatched reqId responseErrorsConfig userInfo reqHdrs apiType reqs =
             . encJFromList
             . map (either (encJFromJValue . encodeGQErr includeInternal) _hrBody)
           try = flip catchError (pure . Left) . fmap Right
-      removeHeaders <$> traverse (try . runGQ reqId userInfo reqHdrs apiType) batch
+      removeHeaders <$> traverse (try . runGQ reqId userInfo reqHdrs queryType) batch
 
 runHasuraGQ
   :: ( MonadIO m
diff --git a/server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs b/server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs
index f5abf6e2a1a4d..20fcfa984ebb1 100644
--- a/server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs
+++ b/server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs
@@ -94,7 +94,7 @@ data WSConnData
   -- are not tracked here
   , _wscOpMap     :: !OperationMap
   , _wscErrRespTy :: !ErrRespType
-  , _wscAPIType   :: !E.GraphQLAPIType
+  , _wscAPIType   :: !E.GraphQLQueryType
   }
 
 type WSServer = WS.WSServer WSConnData
@@ -204,10 +204,10 @@ onConn :: (MonadIO m)
        => L.Logger L.Hasura -> CorsPolicy -> WS.OnConnH m WSConnData
 onConn (L.Logger logger) corsPolicy wsId requestHead = do
   res <- runExceptT $ do
-    (errType, apiType) <- checkPath
+    (errType, queryType) <- checkPath
     let reqHdrs = WS.requestHeaders requestHead
     headers <- maybe (return reqHdrs) (flip enforceCors reqHdrs . snd) getOrigin
-    return (WsHeaders $ filterWsHeaders headers, errType, apiType)
+    return (WsHeaders $ filterWsHeaders headers, errType, queryType)
   either reject accept res
 
   where
@@ -226,13 +226,13 @@ onConn (L.Logger logger) corsPolicy wsId requestHead = do
       currTime <- TC.getCurrentTime
       sleep $ convertDuration $ TC.diffUTCTime expTime currTime
 
-    accept (hdrs, errType, apiType) = do
+    accept (hdrs, errType, queryType) = do
       logger $ mkWsInfoLog Nothing (WsConnInfo wsId Nothing Nothing) EAccepted
       connData <- liftIO $ WSConnData
                   <$> STM.newTVarIO (CSNotInitialised hdrs)
                   <*> STMMap.newIO
                   <*> pure errType
-                  <*> pure apiType
+                  <*> pure queryType
       let acceptRequest = WS.defaultAcceptRequest
                           { WS.acceptSubprotocol = Just "graphql-ws"}
       return $ Right $ WS.AcceptWith connData acceptRequest keepAliveAction tokenExpiryHandler
@@ -245,9 +245,9 @@ onConn (L.Logger logger) corsPolicy wsId requestHead = do
         (BL.toStrict $ J.encode $ encodeGQLErr False qErr)
 
     checkPath = case WS.requestPath requestHead of
-      "/v1alpha1/graphql" -> return (ERTLegacy, E.GATGeneral)
-      "/v1/graphql"       -> return (ERTGraphqlCompliant, E.GATGeneral)
-      "/v1/relay"         -> return (ERTGraphqlCompliant, E.GATRelay)
+      "/v1alpha1/graphql" -> return (ERTLegacy, E.QueryHasura)
+      "/v1/graphql"       -> return (ERTGraphqlCompliant, E.QueryHasura)
+      "/v1/relay"         -> return (ERTGraphqlCompliant, E.QueryRelay)
       _                   ->
         throw404 "only '/v1/graphql', '/v1alpha1/graphql' are supported on websockets"
 
@@ -309,7 +309,7 @@ onStart serverEnv wsConn (StartMsg opId q) = catchAndIgnore $ do
   requestId <- getRequestId reqHdrs
   (sc, scVer) <- liftIO getSchemaCache
   execPlanE <- runExceptT $ E.getResolvedExecPlan pgExecCtx
-               planCache userInfo sqlGenCtx enableAL sc scVer apiType httpMgr reqHdrs q
+               planCache userInfo sqlGenCtx enableAL sc scVer queryType httpMgr reqHdrs q
 
   (telemCacheHit, execPlan) <- either (withComplete . preExecErr requestId) return execPlanE
   let execCtx = E.ExecutionCtx logger sqlGenCtx pgExecCtx
@@ -400,7 +400,7 @@ onStart serverEnv wsConn (StartMsg opId q) = catchAndIgnore $ do
     WSServerEnv logger pgExecCtx lqMap getSchemaCache httpMgr _ sqlGenCtx planCache
       _ enableAL = serverEnv
 
-    WSConnData userInfoR opMap errRespTy apiType = WS.getData wsConn
+    WSConnData userInfoR opMap errRespTy queryType = WS.getData wsConn
 
     logOpEv opTy reqId =
       logWSEvent logger wsConn $ EOperation opDet
diff --git a/server/src-lib/Hasura/Server/App.hs b/server/src-lib/Hasura/Server/App.hs
index 54e9e6051cffc..4b0159b992d5e 100644
--- a/server/src-lib/Hasura/Server/App.hs
+++ b/server/src-lib/Hasura/Server/App.hs
@@ -319,8 +319,8 @@ v1QueryHandler query = do
 
 v1Alpha1GQHandler
   :: (HasVersion, MonadIO m)
-  => E.GraphQLAPIType -> GH.GQLBatchedReqs GH.GQLQueryText -> Handler m (HttpResponse EncJSON)
-v1Alpha1GQHandler apiType query = do
+  => E.GraphQLQueryType -> GH.GQLBatchedReqs GH.GQLQueryText -> Handler m (HttpResponse EncJSON)
+v1Alpha1GQHandler queryType query = do
   userInfo <- asks hcUser
   reqHeaders <- asks hcReqHeaders
   manager <- scManager . hcServerCtx <$> ask
@@ -336,18 +336,18 @@ v1Alpha1GQHandler apiType query = do
   let execCtx = E.ExecutionCtx logger sqlGenCtx pgExecCtx planCache
                 (lastBuiltSchemaCache sc) scVer manager enableAL
   flip runReaderT execCtx $
-    GH.runGQBatched requestId responseErrorsConfig userInfo reqHeaders apiType query
+    GH.runGQBatched requestId responseErrorsConfig userInfo reqHeaders queryType query
 
 v1GQHandler
   :: (HasVersion, MonadIO m)
   => GH.GQLBatchedReqs GH.GQLQueryText
   -> Handler m (HttpResponse EncJSON)
-v1GQHandler = v1Alpha1GQHandler E.GATGeneral
+v1GQHandler = v1Alpha1GQHandler E.QueryHasura
 
 v1GQRelayHandler
   :: (HasVersion, MonadIO m)
   => GH.GQLBatchedReqs GH.GQLQueryText -> Handler m (HttpResponse EncJSON)
-v1GQRelayHandler = v1Alpha1GQHandler E.GATRelay
+v1GQRelayHandler = v1Alpha1GQHandler E.QueryRelay
 
 gqlExplainHandler :: (HasVersion, MonadIO m) => GE.GQLExplain -> Handler m (HttpResponse EncJSON)
 gqlExplainHandler query = do
@@ -616,7 +616,7 @@ httpApp corsCfg serverCtx enableConsole consoleAssetsDir enableTelemetry = do
 
     when enableGraphQL $ do
       Spock.post "v1alpha1/graphql" $ spockAction GH.encodeGQErr id $
-        mkPostHandler $ mkAPIRespHandler $ v1Alpha1GQHandler E.GATGeneral
+        mkPostHandler $ mkAPIRespHandler $ v1Alpha1GQHandler E.QueryHasura
 
       Spock.post "v1/graphql" $ spockAction GH.encodeGQErr allMod200 $
         mkPostHandler $ mkAPIRespHandler v1GQHandler

From 2759f25bdfc4584f37a4baa75d1a8f2b6a15ad9c Mon Sep 17 00:00:00 2001
From: rakeshkky <12475069+rakeshkky@users.noreply.github.com>
Date: Wed, 27 May 2020 20:26:39 +0530
Subject: [PATCH 13/29] add hasura mutations to relay

---
 server/src-lib/Hasura/GraphQL/RelaySchema.hs  | 120 ++++++---
 server/src-lib/Hasura/GraphQL/Schema.hs       | 244 +++++++++++-------
 .../src-lib/Hasura/GraphQL/Schema/Builder.hs  |   9 +-
 3 files changed, 247 insertions(+), 126 deletions(-)

diff --git a/server/src-lib/Hasura/GraphQL/RelaySchema.hs b/server/src-lib/Hasura/GraphQL/RelaySchema.hs
index ac17acf23aaab..d24cf542977ca 100644
--- a/server/src-lib/Hasura/GraphQL/RelaySchema.hs
+++ b/server/src-lib/Hasura/GraphQL/RelaySchema.hs
@@ -41,7 +41,7 @@ mkRelayGCtxMap tableCache functionCache = do
   typesMapL <- mapM (mkRelayGCtxMapTable tableCache functionCache) relayTables
   typesMap <- combineTypes typesMapL
   let gCtxMap  = flip Map.map typesMap $
-                 \(ty, flds) -> mkGCtx ty flds mempty
+                 \(ty, flds, insCtx) -> mkGCtx ty flds insCtx
   pure $ Map.map (flip RoleContext Nothing) gCtxMap
   where
     relayTables =
@@ -53,8 +53,8 @@ mkRelayGCtxMap tableCache functionCache = do
       && isJust (_tciPrimaryKey ti)
 
     combineTypes
-      :: [Map.HashMap RoleName (TyAgg, RootFields)]
-      -> m (Map.HashMap RoleName (TyAgg, RootFields))
+      :: [Map.HashMap RoleName (TyAgg, RootFields, InsCtxMap)]
+      -> m (Map.HashMap RoleName (TyAgg, RootFields, InsCtxMap))
     combineTypes maps = do
       let listMap = foldr (Map.unionWith (++) . Map.map pure) mempty maps
       flip Map.traverseWithKey listMap $ \roleName typeList -> do
@@ -62,8 +62,9 @@ mkRelayGCtxMap tableCache functionCache = do
             tyAgg = addTypeInfoToTyAgg
                     (TIIFace $ mkNodeInterface relayTableNames) $
                     mconcat $ map (^. _1) typeList
+            insCtx = mconcat $ map (^. _3) typeList
         rootFields <- combineRootFields roleName $ map (^. _2) typeList
-        pure (tyAgg, rootFields)
+        pure (tyAgg, rootFields, insCtx)
 
     combineRootFields :: RoleName -> [RootFields] -> m RootFields
     combineRootFields roleName rootFields = do
@@ -88,22 +89,37 @@ mkRelayGCtxMapTable
   => TableCache
   -> FunctionCache
   -> TableInfo
-  -> m (Map.HashMap RoleName (TyAgg, RootFields))
+  -> m (Map.HashMap RoleName (TyAgg, RootFields, InsCtxMap))
 mkRelayGCtxMapTable tableCache funcCache tabInfo = do
   m <- flip Map.traverseWithKey rolePerms $
-       mkRelayGCtxRole tableCache tn descM fields primaryKey tabFuncs
+       mkRelayGCtxRole tableCache tn descM fields primaryKey validConstraints  tabFuncs viewInfo customConfig
   adminSelFlds <- mkAdminSelFlds fields tableCache
-  let adminCtx = mkRelayGCtxRole' tn descM (Just (True, adminSelFlds))
-                 primaryKey tabFuncs
-  return $ Map.insert adminRoleName (adminCtx, adminRootFlds) m
+  adminInsCtx <- mkAdminInsCtx tableCache fields
+  let adminCtx = mkRelayTyAggRole tn descM (Just (cols, icRelations adminInsCtx))
+                 (Just (True, adminSelFlds)) (Just cols) (Just ())
+                 primaryKey validConstraints viewInfo tabFuncs
+      adminInsCtxMap = Map.singleton tn adminInsCtx
+  return $ Map.insert adminRoleName (adminCtx, adminRootFlds, adminInsCtxMap) m
   where
     TableInfo coreInfo rolePerms _ = tabInfo
-    TableCoreInfo tn descM _ fields primaryKey _ _ _ _ _ = coreInfo
+    TableCoreInfo tn descM _ fields primaryKey _ _ viewInfo _ customConfig = coreInfo
+    validConstraints = mkValidConstraints $ map _cName (tciUniqueOrPrimaryKeyConstraints coreInfo)
     tabFuncs = filter (isValidObjectName . fiName) $
                getFuncsOfTable tn funcCache
+    cols = getValidCols fields
     adminRootFlds =
-      getRelayRootFldsRole' tn primaryKey fields tabFuncs
-      (Just (noFilter, Nothing, [], True))
+      let insertPermDetails = Just ([], True)
+          selectPermDetails = Just (noFilter, Nothing, [], True)
+          updatePermDetails = Just (getValidCols fields, mempty, noFilter, Nothing, [])
+          deletePermDetails = Just (noFilter, [])
+
+          queryFields = getRelayQueryRootFieldsRole tn primaryKey fields tabFuncs
+                        selectPermDetails
+          mutationFields = getMutationRootFieldsRole tn primaryKey
+                           validConstraints fields insertPermDetails
+                           selectPermDetails updatePermDetails
+                           deletePermDetails viewInfo customConfig
+      in RootFields queryFields mutationFields
 
 mkRelayGCtxRole
   :: (MonadError QErr m)
@@ -112,33 +128,73 @@ mkRelayGCtxRole
   -> Maybe PGDescription
   -> FieldInfoMap FieldInfo
   -> Maybe (PrimaryKey PGColumnInfo)
+  -> [ConstraintName]
   -> [FunctionInfo]
+  -> Maybe ViewInfo
+  -> TableConfig
   -> RoleName
   -> RolePermInfo
-  -> m (TyAgg, RootFields)
-mkRelayGCtxRole tableCache tn descM fields primaryKey funcs role permInfo = do
-  selPermM <- mapM (getSelPerm tableCache fields role) $ _permSel permInfo
-  let tyAgg = mkRelayGCtxRole' tn descM selPermM primaryKey funcs
-      rootFlds = getRelayRootFldsRole' tn primaryKey fields funcs
+  -> m (TyAgg, RootFields, InsCtxMap)
+mkRelayGCtxRole tableCache tn descM fields primaryKey constraints funcs viM tabConfigM role permInfo = do
+  selPermM <- mapM (getSelPerm tableCache fields role) selM
+  tabInsInfoM <- forM (_permIns permInfo) $ \ipi -> do
+    ctx <- mkInsCtx role tableCache fields ipi $ _permUpd permInfo
+    let permCols = flip getColInfos allCols $ Set.toList $ ipiCols ipi
+    return (ctx, (permCols, icRelations ctx))
+  let insPermM = snd <$> tabInsInfoM
+      insCtxM = fst <$> tabInsInfoM
+      updColsM = filterColumnFields . upiCols <$> _permUpd permInfo
+      tyAgg = mkRelayTyAggRole tn descM insPermM selPermM updColsM
+              (void $ _permDel permInfo) primaryKey constraints viM funcs
+      queryRootFlds = getRelayQueryRootFieldsRole tn primaryKey fields funcs
                  (mkSel <$> _permSel permInfo)
-  return (tyAgg, rootFlds)
+      mutationRootFlds = getMutationRootFieldsRole tn primaryKey constraints fields
+                       (mkIns <$> insM) (mkSel <$> selM)
+                       (mkUpd <$> updM) (mkDel <$> delM) viM tabConfigM
+      insCtxMap = maybe Map.empty (Map.singleton tn) insCtxM
+  return (tyAgg, RootFields queryRootFlds mutationRootFlds, insCtxMap)
   where
+    RolePermInfo insM selM updM delM = permInfo
+    allCols = getCols fields
+    filterColumnFields allowedSet =
+      filter ((`Set.member` allowedSet) . pgiColumn) $ getValidCols fields
+    mkIns i = (ipiRequiredHeaders i, isJust updM)
     mkSel s = ( spiFilter s, spiLimit s
               , spiRequiredHeaders s, spiAllowAgg s
               )
+    mkUpd u = ( flip getColInfos allCols $ Set.toList $ upiCols u
+              , upiSet u
+              , upiFilter u
+              , upiCheck u
+              , upiRequiredHeaders u
+              )
+    mkDel d = (dpiFilter d, dpiRequiredHeaders d)
 
-mkRelayGCtxRole'
+mkRelayTyAggRole
   :: QualifiedTable
   -> Maybe PGDescription
   -- ^ Postgres description
+  -> Maybe ([PGColumnInfo], RelationInfoMap)
+  -- ^ insert permission
   -> Maybe (Bool, [SelField])
   -- ^ select permission
+  -> Maybe [PGColumnInfo]
+  -- ^ update cols
+  -> Maybe ()
+  -- ^ delete cols
   -> Maybe (PrimaryKey PGColumnInfo)
+  -> [ConstraintName]
+  -- ^ constraints
+  -> Maybe ViewInfo
   -> [FunctionInfo]
   -- ^ all functions
   -> TyAgg
-mkRelayGCtxRole' tn descM selPermM pkeyCols funcs =
-  TyAgg (mkTyInfoMap allTypes) fieldMap scalars ordByCtx
+mkRelayTyAggRole tn descM insPermM selPermM updColsM delPermM pkeyCols constraints viM funcs =
+  let (mutationTypes, mutationFields) =
+        mkMutationTypesAndFieldsRole tn insPermM selFldsM updColsM delPermM pkeyCols constraints viM
+  in TyAgg (mkTyInfoMap allTypes <> mutationTypes)
+           (fieldMap <> mutationFields)
+            scalars ordByCtx
   where
     ordByCtx = fromMaybe Map.empty ordByCtxM
 
@@ -161,7 +217,15 @@ mkRelayGCtxRole' tn descM selPermM pkeyCols funcs =
     selColNamesM = (map pgiName . getPGColumnFields) <$> selFldsM
     selColInpTyM = mkSelColumnTy tn <$> selColNamesM
     -- boolexp input type
-    boolExpInpObjM = (mkBoolExpInp tn) <$> selFldsM
+    boolExpInpObjM = case selFldsM of
+      Just selFlds  -> Just $ mkBoolExpInp tn selFlds
+      -- no select permission
+      Nothing ->
+        -- but update/delete is defined
+        if isJust updColsM || isJust delPermM
+        then Just $ mkBoolExpInp tn []
+        else Nothing
+
     -- funcargs input type
     funcArgInpObjs = flip mapMaybe funcs $ \func ->
       mkFuncArgsInp (fiName func) (getInputArgs func)
@@ -270,25 +334,21 @@ mkSelectOpCtx tn allCols (fltr, pLimit, hdrs) =
   where
     colGNameMap = mkPGColGNameMap allCols
 
-getRelayRootFldsRole'
+getRelayQueryRootFieldsRole
   :: QualifiedTable
   -> Maybe (PrimaryKey PGColumnInfo)
   -> FieldInfoMap FieldInfo
   -> [FunctionInfo]
   -> Maybe (AnnBoolExpPartialSQL, Maybe Int, [T.Text], Bool) -- select filter
-  -> RootFields
-getRelayRootFldsRole' tn primaryKey fields funcs selM =
-  RootFields
-    { _rootQueryFields = makeFieldMap $
+  -> QueryRootFieldMap
+getRelayQueryRootFieldsRole tn primaryKey fields funcs selM =
+    makeFieldMap $
         funcConnectionQueries
         <> catMaybes
           [ getSelConnectionDet <$> selM <*> maybePrimaryKeyColumns
           ]
-    , _rootMutationFields = mempty
-    }
   where
     maybePrimaryKeyColumns = fmap _pkColumns primaryKey
-    makeFieldMap = mapFromL (_fiName . snd)
     colGNameMap = mkPGColGNameMap $ getCols fields
 
     funcConnectionQueries = fromMaybe [] $ getFuncQueryConnectionFlds
diff --git a/server/src-lib/Hasura/GraphQL/Schema.hs b/server/src-lib/Hasura/GraphQL/Schema.hs
index 45415d3bf9fbc..52caf58fdfd3d 100644
--- a/server/src-lib/Hasura/GraphQL/Schema.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema.hs
@@ -1,6 +1,5 @@
 module Hasura.GraphQL.Schema
   ( mkGCtxMap
-  , mkGCtx
   , GCtxMap
   , GCtx(..)
   , QueryCtx(..)
@@ -8,6 +7,12 @@ module Hasura.GraphQL.Schema
   , InsCtx(..)
   , InsCtxMap
   , RelationInfoMap
+
+  , checkConflictingNode
+  , checkSchemaConflicts
+
+  -- * To be consumed by Hasura.GraphQL.RelaySchema module
+  , mkGCtx
   , isAggregateField
   , qualObjectToName
   , ppGCtx
@@ -16,9 +21,13 @@ module Hasura.GraphQL.Schema
   , mkAdminSelFlds
   , noFilter
   , getGCtx
-
-  , checkConflictingNode
-  , checkSchemaConflicts
+  , getMutationRootFieldsRole
+  , makeFieldMap
+  , mkMutationTypesAndFieldsRole
+  , mkAdminInsCtx
+  , mkValidConstraints
+  , getValidCols
+  , mkInsCtx
   ) where
 
 import           Control.Lens.Extended                 hiding (op)
@@ -112,14 +121,11 @@ mkComputedFieldFunctionArgSeq inputArgs =
     Seq.fromList $ procFuncArgs inputArgs faName $
     \fa t -> FunctionArgItem (G.Name t) (faName fa) (faHasDefault fa)
 
--- see Note [Split schema generation (TODO)]
-mkGCtxRole'
+mkMutationTypesAndFieldsRole
   :: QualifiedTable
-  -> Maybe PGDescription
-  -- ^ Postgres description
   -> Maybe ([PGColumnInfo], RelationInfoMap)
   -- ^ insert permission
-  -> Maybe (Bool, [SelField])
+  -> Maybe [SelField]
   -- ^ select permission
   -> Maybe [PGColumnInfo]
   -- ^ update cols
@@ -129,14 +135,14 @@ mkGCtxRole'
   -> [ConstraintName]
   -- ^ constraints
   -> Maybe ViewInfo
-  -> [FunctionInfo]
-  -- ^ all functions
-  -> TyAgg
-mkGCtxRole' tn descM insPermM selPermM updColsM delPermM pkeyCols constraints viM funcs =
-  TyAgg (mkTyInfoMap allTypes) fieldMap scalars ordByCtx
+  -> (TypeMap, FieldMap)
+mkMutationTypesAndFieldsRole tn insPermM selFldsM updColsM delPermM pkeyCols constraints viM =
+  (mkTyInfoMap allTypes, fieldMap)
   where
 
-    ordByCtx = fromMaybe Map.empty ordByCtxM
+    allTypes = relInsInpObjTys <> onConflictTypes <> jsonOpTys
+               <> mutationTypes <> referencedEnumTypes
+
     upsertPerm = isJust updColsM
     isUpsertable = upsertable constraints upsertPerm $ isJust viM
     updatableCols = maybe [] (map pgiName) updColsM
@@ -145,36 +151,18 @@ mkGCtxRole' tn descM insPermM selPermM updColsM delPermM pkeyCols constraints vi
     relInsInpObjTys = maybe [] (map TIInpObj) $
                       mutHelper viIsInsertable relInsInpObjsM
 
-    funcInpArgTys = bool [] (map TIInpObj funcArgInpObjs) $ isJust selFldsM
-
-    allTypes = relInsInpObjTys <> onConflictTypes <> jsonOpTys
-               <> queryTypes <> aggQueryTypes <> mutationTypes
-               <> funcInpArgTys <> referencedEnumTypes <> computedFieldFuncArgsInps
-
-    queryTypes = map TIObj selectObjects <>
-      catMaybes
-      [ TIInpObj <$> boolExpInpObjM
-      , TIInpObj <$> ordByInpObjM
-      ]
-    aggQueryTypes = map TIObj aggObjs <> map TIInpObj aggOrdByInps
-
     mutationTypes = catMaybes
       [ TIInpObj <$> mutHelper viIsInsertable insInpObjM
       , TIInpObj <$> mutHelper viIsUpdatable updSetInpObjM
       , TIInpObj <$> mutHelper viIsUpdatable updIncInpObjM
       , TIInpObj <$> mutHelper viIsUpdatable primaryKeysInpObjM
       , TIObj <$> mutRespObjM
-      , TIEnum <$> selColInpTyM
       ]
 
     mutHelper :: (ViewInfo -> Bool) -> Maybe a -> Maybe a
     mutHelper f objM = bool Nothing objM $ isMutable f viM
 
-    fieldMap = Map.unions $ catMaybes
-               [ insInpObjFldsM, updSetInpObjFldsM
-               , boolExpInpObjFldsM , selObjFldsM
-               ]
-    scalars = selByPkScalarSet <> funcArgScalarSet <> computedFieldFuncArgScalars
+    fieldMap = Map.unions $ catMaybes [insInpObjFldsM, updSetInpObjFldsM]
 
     -- helper
     mkColFldMap ty cols = Map.fromList $ flip map cols $
@@ -185,7 +173,7 @@ mkGCtxRole' tn descM insPermM selPermM updColsM delPermM pkeyCols constraints vi
     -- column fields used in insert input object
     insInpObjFldsM = (mkColFldMap (mkInsInpTy tn) . fst) <$> insPermM
     -- relationship input objects
-    relInsInpObjsM = const (mkRelInsInps tn isUpsertable) <$> insPermM
+    relInsInpObjsM = mkRelInsInps tn isUpsertable <$ insPermM
     -- update set input type
     updSetInpObjM = mkUpdSetInp tn <$> updColsM
     -- update increment input type
@@ -197,7 +185,74 @@ mkGCtxRole' tn descM insPermM selPermM updColsM delPermM pkeyCols constraints vi
     updSetInpObjFldsM = mkColFldMap (mkUpdSetTy tn) <$> updColsM
 
     -- primary key columns input object for update_by_pk
-    primaryKeysInpObjM = guard (isJust selPermM) *> (mkPKeyColumnsInpObj tn <$> pkeyCols)
+    primaryKeysInpObjM = guard (isJust selFldsM) *> (mkPKeyColumnsInpObj tn <$> pkeyCols)
+
+    -- mut resp obj
+    mutRespObjM =
+      if isMut
+      then Just $ mkMutRespObj tn $ isJust selFldsM
+      else Nothing
+
+    isMut = (isJust insPermM || isJust updColsM || isJust delPermM)
+            && any (`isMutable` viM) [viIsInsertable, viIsUpdatable, viIsDeletable]
+
+    -- the types for all enums that are /referenced/ by this table (not /defined/ by this table;
+    -- there isn’t actually any need to generate a GraphQL enum type for an enum table if it’s
+    -- never referenced anywhere else)
+    referencedEnumTypes =
+      let allColumnInfos =
+               (selFldsM ^.. _Just.traverse._SFPGColumn)
+            <> (insPermM ^. _Just._1)
+            <> (updColsM ^. _Just)
+          allEnumReferences = allColumnInfos ^.. traverse.to pgiType._PGColumnEnumReference
+      in flip map allEnumReferences $ \enumReference@(EnumReference referencedTableName _) ->
+           let typeName = mkTableEnumType referencedTableName
+           in TIEnum $ mkHsraEnumTyInfo Nothing typeName (EnumValuesReference enumReference)
+
+-- see Note [Split schema generation (TODO)]
+mkTyAggRole
+  :: QualifiedTable
+  -> Maybe PGDescription
+  -- ^ Postgres description
+  -> Maybe ([PGColumnInfo], RelationInfoMap)
+  -- ^ insert permission
+  -> Maybe (Bool, [SelField])
+  -- ^ select permission
+  -> Maybe [PGColumnInfo]
+  -- ^ update cols
+  -> Maybe ()
+  -- ^ delete cols
+  -> Maybe (PrimaryKey PGColumnInfo)
+  -> [ConstraintName]
+  -- ^ constraints
+  -> Maybe ViewInfo
+  -> [FunctionInfo]
+  -- ^ all functions
+  -> TyAgg
+mkTyAggRole tn descM insPermM selPermM updColsM delPermM pkeyCols constraints viM funcs =
+  let (mutationTypes, mutationFields) =
+        mkMutationTypesAndFieldsRole tn insPermM selFldsM updColsM delPermM pkeyCols constraints viM
+  in TyAgg (mkTyInfoMap allTypes <> mutationTypes)
+           (fieldMap <> mutationFields)
+            scalars ordByCtx
+  where
+
+    ordByCtx = fromMaybe Map.empty ordByCtxM
+    funcInpArgTys = bool [] (map TIInpObj funcArgInpObjs) $ isJust selFldsM
+
+    allTypes = queryTypes <> aggQueryTypes
+               <> funcInpArgTys <> computedFieldFuncArgsInps
+
+    queryTypes = map TIObj selectObjects <>
+      catMaybes
+      [ TIInpObj <$> boolExpInpObjM
+      , TIInpObj <$> ordByInpObjM
+      , TIEnum <$> selColInpTyM
+      ]
+    aggQueryTypes = map TIObj aggObjs <> map TIInpObj aggOrdByInps
+
+    fieldMap = Map.unions $ catMaybes [boolExpInpObjFldsM , selObjFldsM]
+    scalars = selByPkScalarSet <> funcArgScalarSet <> computedFieldFuncArgScalars
 
     selFldsM = snd <$> selPermM
     selColNamesM = (map pgiName . getPGColumnFields) <$> selFldsM
@@ -241,15 +296,6 @@ mkGCtxRole' tn descM insPermM selPermM updColsM delPermM pkeyCols constraints vi
     -- the fields used in bool exp
     boolExpInpObjFldsM = mkFldMap (mkBoolExpTy tn) <$> selFldsM
 
-    -- mut resp obj
-    mutRespObjM =
-      if isMut
-      then Just $ mkMutRespObj tn $ isJust selFldsM
-      else Nothing
-
-    isMut = (isJust insPermM || isJust updColsM || isJust delPermM)
-            && any (`isMutable` viM) [viIsInsertable, viIsUpdatable, viIsDeletable]
-
     -- table obj
     selectObjects = case selPermM of
       Just (_, selFlds) ->
@@ -296,20 +342,6 @@ mkGCtxRole' tn descM insPermM selPermM updColsM delPermM pkeyCols constraints vi
       Just (a, b) -> (Just a, Just b)
       Nothing     -> (Nothing, Nothing)
 
-    -- the types for all enums that are /referenced/ by this table (not /defined/ by this table;
-    -- there isn’t actually any need to generate a GraphQL enum type for an enum table if it’s
-    -- never referenced anywhere else)
-    referencedEnumTypes =
-      let allColumnInfos =
-               (selPermM ^.. _Just._2.traverse._SFPGColumn)
-            <> (insPermM ^. _Just._1)
-            <> (updColsM ^. _Just)
-          allEnumReferences = allColumnInfos ^.. traverse.to pgiType._PGColumnEnumReference
-      in flip map allEnumReferences $ \enumReference@(EnumReference referencedTableName _) ->
-           let typeName = mkTableEnumType referencedTableName
-           in TIEnum $ mkHsraEnumTyInfo Nothing typeName (EnumValuesReference enumReference)
-
-
     -- computed fields' function args input objects and scalar types
     mkComputedFieldRequiredTypes computedFieldInfo =
       let ComputedFieldFunction qf inputArgs _ _ _ = _cfFunction computedFieldInfo
@@ -322,32 +354,25 @@ mkGCtxRole' tn descM insPermM selPermM updColsM delPermM pkeyCols constraints vi
     computedFieldFuncArgsInps = map (TIInpObj . fst) computedFieldReqTypes
     computedFieldFuncArgScalars = Set.fromList $ concatMap snd computedFieldReqTypes
 
+makeFieldMap :: [(a, ObjFldInfo)] -> Map.HashMap G.Name (a, ObjFldInfo)
+makeFieldMap = mapFromL (_fiName . snd)
+
 -- see Note [Split schema generation (TODO)]
-getRootFldsRole'
+getMutationRootFieldsRole
   :: QualifiedTable
   -> Maybe (PrimaryKey PGColumnInfo)
   -> [ConstraintName]
   -> FieldInfoMap FieldInfo
-  -> [FunctionInfo]
   -> Maybe ([T.Text], Bool) -- insert perm
   -> Maybe (AnnBoolExpPartialSQL, Maybe Int, [T.Text], Bool) -- select filter
   -> Maybe ([PGColumnInfo], PreSetColsPartial, AnnBoolExpPartialSQL, Maybe AnnBoolExpPartialSQL, [T.Text]) -- update filter
   -> Maybe (AnnBoolExpPartialSQL, [T.Text]) -- delete filter
   -> Maybe ViewInfo
   -> TableConfig -- custom config
-  -> RootFields
-getRootFldsRole' tn primaryKey constraints fields funcs insM
-                 selM updM delM viM tableConfig =
-  RootFields
-    { _rootQueryFields = makeFieldMap $
-        funcQueries
-        <> funcAggQueries
-        <> catMaybes
-          [ getSelDet <$> selM
-          , getSelAggDet selM
-          , getPKeySelDet <$> selM <*> primaryKey
-          ]
-    , _rootMutationFields = makeFieldMap $ catMaybes
+  -> MutationRootFieldMap
+getMutationRootFieldsRole tn primaryKey constraints fields insM
+                           selM updM delM viM tableConfig =
+    makeFieldMap $ catMaybes
         [ mutHelper viIsInsertable getInsDet insM
         , onlyIfSelectPermExist $ mutHelper viIsInsertable getInsOneDet insM
         , mutHelper viIsUpdatable getUpdDet updM
@@ -355,15 +380,10 @@ getRootFldsRole' tn primaryKey constraints fields funcs insM
         , mutHelper viIsDeletable getDelDet delM
         , onlyIfSelectPermExist $ mutHelper viIsDeletable getDelByPkDet $ (,) <$> delM <*> primaryKey
         ]
-    }
   where
-    makeFieldMap = mapFromL (_fiName . snd)
     customRootFields = _tcCustomRootFields tableConfig
     colGNameMap = mkPGColGNameMap $ getCols fields
 
-    funcQueries = maybe [] getFuncQueryFlds selM
-    funcAggQueries = maybe [] getFuncAggQueryFlds selM
-
     mutHelper :: (ViewInfo -> Bool) -> (a -> b) -> Maybe a -> Maybe b
     mutHelper f getDet mutM =
       bool Nothing (getDet <$> mutM) $ isMutable f viM
@@ -409,6 +429,32 @@ getRootFldsRole' tn primaryKey constraints fields funcs insM
       , mkDeleteByPkMutationField delByPkCustName tn pKey
       )
 
+-- see Note [Split schema generation (TODO)]
+getQueryRootFieldsRole
+  :: QualifiedTable
+  -> Maybe (PrimaryKey PGColumnInfo)
+  -> FieldInfoMap FieldInfo
+  -> [FunctionInfo]
+  -> Maybe (AnnBoolExpPartialSQL, Maybe Int, [T.Text], Bool) -- select filter
+  -> TableConfig -- custom config
+  -> QueryRootFieldMap
+getQueryRootFieldsRole tn primaryKey fields funcs selM tableConfig =
+  makeFieldMap $
+           funcQueries
+        <> funcAggQueries
+        <> catMaybes
+          [ getSelDet <$> selM
+          , getSelAggDet selM
+          , getPKeySelDet <$> selM <*> primaryKey
+          ]
+  where
+    customRootFields = _tcCustomRootFields tableConfig
+    colGNameMap = mkPGColGNameMap $ getCols fields
+
+    funcQueries = maybe [] getFuncQueryFlds selM
+    funcAggQueries = maybe [] getFuncAggQueryFlds selM
+
+    getCustomNameWith f = f customRootFields
 
     selCustName = getCustomNameWith _tcrfSelect
     getSelDet (selFltr, pLimit, hdrs, _) =
@@ -638,7 +684,7 @@ mkGCtxRole tableCache tn descM fields primaryKey constraints funcs viM tabConfig
   let insPermM = snd <$> tabInsInfoM
       insCtxM = fst <$> tabInsInfoM
       updColsM = filterColumnFields . upiCols <$> _permUpd permInfo
-      tyAgg = mkGCtxRole' tn descM insPermM selPermM updColsM
+      tyAgg = mkTyAggRole tn descM insPermM selPermM updColsM
               (void $ _permDel permInfo) primaryKey constraints viM funcs
       rootFlds = getRootFldsRole tn primaryKey constraints fields funcs
                  viM permInfo tabConfigM
@@ -660,10 +706,12 @@ getRootFldsRole
   -> RolePermInfo
   -> TableConfig
   -> RootFields
-getRootFldsRole tn pCols constraints fields funcs viM (RolePermInfo insM selM updM delM)=
-  getRootFldsRole' tn pCols constraints fields funcs
-  (mkIns <$> insM) (mkSel <$> selM)
-  (mkUpd <$> updM) (mkDel <$> delM) viM
+getRootFldsRole tn pCols constraints fields funcs viM (RolePermInfo insM selM updM delM) tableConfig =
+  let queryFields = getQueryRootFieldsRole tn pCols fields funcs (mkSel <$> selM) tableConfig
+      mutationFields = getMutationRootFieldsRole tn pCols constraints fields
+                       (mkIns <$> insM) (mkSel <$> selM)
+                       (mkUpd <$> updM) (mkDel <$> delM) viM tableConfig
+  in RootFields queryFields mutationFields
   where
     mkIns i = (ipiRequiredHeaders i, isJust updM)
     mkSel s = ( spiFilter s, spiLimit s
@@ -691,7 +739,7 @@ mkGCtxMapTable tableCache funcCache tabInfo = do
                              tabFuncs viewInfo customConfig roleName
   adminInsCtx <- mkAdminInsCtx tableCache fields
   adminSelFlds <- mkAdminSelFlds fields tableCache
-  let adminCtx = mkGCtxRole' tn descM (Just (cols, icRelations adminInsCtx))
+  let adminCtx = mkTyAggRole tn descM (Just (cols, icRelations adminInsCtx))
                  (Just (True, adminSelFlds)) (Just cols) (Just ())
                  primaryKey validConstraints viewInfo tabFuncs
       adminInsCtxMap = Map.singleton tn adminInsCtx
@@ -705,10 +753,18 @@ mkGCtxMapTable tableCache funcCache tabInfo = do
     tabFuncs = filter (isValidObjectName . fiName) $ getFuncsOfTable tn funcCache
 
     adminRootFlds =
-      getRootFldsRole' tn primaryKey validConstraints fields tabFuncs
-      (Just ([], True)) (Just (noFilter, Nothing, [], True))
-      (Just (cols, mempty, noFilter, Nothing, [])) (Just (noFilter, []))
-      viewInfo customConfig
+      let insertPermDetails = Just ([], True)
+          selectPermDetails = Just (noFilter, Nothing, [], True)
+          updatePermDetails = Just (cols, mempty, noFilter, Nothing, [])
+          deletePermDetails = Just (noFilter, [])
+
+          queryFields = getQueryRootFieldsRole tn primaryKey fields tabFuncs
+                        selectPermDetails customConfig
+          mutationFields = getMutationRootFieldsRole tn primaryKey
+                           validConstraints fields insertPermDetails
+                           selectPermDetails updatePermDetails
+                           deletePermDetails viewInfo customConfig
+      in RootFields queryFields mutationFields
 
     rolePermsMap :: Map.HashMap RoleName (RoleContext RolePermInfo)
     rolePermsMap = flip Map.map rolePerms $ \permInfo ->
@@ -730,11 +786,11 @@ noFilter = annBoolExpTrue
 
 {- Note [Split schema generation (TODO)]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-As of writing this, the schema is generated per table per role and for all permissions.
-See functions  "mkGCtxRole'" and "getRootFldsRole'". This approach makes hard to
-differentiate schema generation for each operation (select, insert, delete and update)
-based on respective permission information and safe merging those schemas eventually.
-For backend-only inserts (see https://github.com/hasura/graphql-engine/pull/4224)
+As of writing this, the schema is generated per table per role and for queries and mutations
+separately. See functions  "mkTyAggRole", "getQueryRootFieldsRole" and "getMutationRootFieldsRole".
+This approach makes hard to differentiate schema generation for each operation
+(select, insert, delete and update) based on respective permission information and safe merging
+those schemas eventually. For backend-only inserts (see https://github.com/hasura/graphql-engine/pull/4224)
 we need to somehow defer the logic of merging schema for inserts with others based on its
 backend-only credibility. This requires significant refactor of this module and
 we can't afford to do it as of now since we're going to rewrite the entire GraphQL schema
diff --git a/server/src-lib/Hasura/GraphQL/Schema/Builder.hs b/server/src-lib/Hasura/GraphQL/Schema/Builder.hs
index af486bab86b55..b4d4230db8f06 100644
--- a/server/src-lib/Hasura/GraphQL/Schema/Builder.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/Builder.hs
@@ -8,6 +8,8 @@ module Hasura.GraphQL.Schema.Builder
   , addFieldsToTyAgg
   , addTypeInfoToTyAgg
   , addScalarToTyAgg
+  , QueryRootFieldMap
+  , MutationRootFieldMap
   , RootFields(..)
   , addQueryField
   , addMutationField
@@ -57,11 +59,14 @@ instance Semigroup TyAgg where
 instance Monoid TyAgg where
   mempty = TyAgg Map.empty Map.empty Set.empty Map.empty
 
+type QueryRootFieldMap = Map.HashMap G.Name (QueryCtx, ObjFldInfo)
+type MutationRootFieldMap = Map.HashMap G.Name (MutationCtx, ObjFldInfo)
+
 -- | A role-specific mapping from root field names to allowed operations.
 data RootFields
   = RootFields
-  { _rootQueryFields    :: !(Map.HashMap G.Name (QueryCtx, ObjFldInfo))
-  , _rootMutationFields :: !(Map.HashMap G.Name (MutationCtx, ObjFldInfo))
+  { _rootQueryFields    :: !QueryRootFieldMap
+  , _rootMutationFields :: !MutationRootFieldMap
   } deriving (Show, Eq)
 $(makeLenses ''RootFields)
 

From a36102d24cb2edae0f4c79f39c872557452ee658 Mon Sep 17 00:00:00 2001
From: Rikin Kachhia <54616969+rikinsk@users.noreply.github.com>
Date: Thu, 28 May 2020 18:24:36 +0530
Subject: [PATCH 14/29] update relay toggle margin

---
 console/src/components/Services/ApiExplorer/ApiExplorer.scss | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/console/src/components/Services/ApiExplorer/ApiExplorer.scss b/console/src/components/Services/ApiExplorer/ApiExplorer.scss
index 912442f4129e7..6e4f6154549ae 100644
--- a/console/src/components/Services/ApiExplorer/ApiExplorer.scss
+++ b/console/src/components/Services/ApiExplorer/ApiExplorer.scss
@@ -829,6 +829,6 @@ label {
 }
 
 .graphiqlModeToggle {
-  margin-top: -10px;
+  margin-top: -5px;
   float: right;
-}
\ No newline at end of file
+}

From db3d3966cd8bfe86c32552f7789d0e606931cfa3 Mon Sep 17 00:00:00 2001
From: rakeshkky <12475069+rakeshkky@users.noreply.github.com>
Date: Thu, 28 May 2020 18:34:48 +0530
Subject: [PATCH 15/29] fix postgres query error when simple and connection
 array field exist in same query

---
 server/src-lib/Hasura/RQL/DML/Select/Internal.hs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/server/src-lib/Hasura/RQL/DML/Select/Internal.hs b/server/src-lib/Hasura/RQL/DML/Select/Internal.hs
index b64d0f6efecf6..64ca7021989d3 100644
--- a/server/src-lib/Hasura/RQL/DML/Select/Internal.hs
+++ b/server/src-lib/Hasura/RQL/DML/Select/Internal.hs
@@ -314,8 +314,9 @@ getArrayRelNameAndSelectArgs = \case
 
 getAnnArr :: (a, AnnFieldG v) -> Maybe (a, ArraySelectG v)
 getAnnArr (f, annFld) = case annFld of
-  AFArrayRelation ar -> Just (f, ar)
-  _                  -> Nothing
+  AFArrayRelation (ASConnection _) -> Nothing
+  AFArrayRelation ar               -> Just (f, ar)
+  _                                -> Nothing
 
 
 withWriteJoinTree

From 0ec539bf9a42a2f1a550e358812968ccd1230388 Mon Sep 17 00:00:00 2001
From: rakeshkky <12475069+rakeshkky@users.noreply.github.com>
Date: Thu, 28 May 2020 18:56:00 +0530
Subject: [PATCH 16/29] fix top level connection field types in relay

---
 server/src-lib/Hasura/GraphQL/Schema/Select.hs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/server/src-lib/Hasura/GraphQL/Schema/Select.hs b/server/src-lib/Hasura/GraphQL/Schema/Select.hs
index d36239e3a581c..fdb0d13c950bc 100644
--- a/server/src-lib/Hasura/GraphQL/Schema/Select.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/Select.hs
@@ -348,7 +348,7 @@ table(
   where: table_bool_exp
   limit: Int
   offset: Int
-):  [tableConnection!]!
+):  tableConnection!
 
 -}
 
@@ -359,7 +359,7 @@ mkSelFldConnection mCustomName tn =
     desc    = G.Description $ "fetch data from the table: " <>> tn
     fldName = fromMaybe (qualObjectToName tn <> "_connection") mCustomName
     args    = fromInpValL $ mkConnectionArgs tn
-    ty      = G.toGT $ G.toNT $ G.toLT $ G.toNT $ mkTableConnectionTy tn
+    ty      = G.toGT $ G.toNT $ mkTableConnectionTy tn
 
 {-
 type tableConnection {

From 84cef325396b0d1252028dd7ea237da10622298c Mon Sep 17 00:00:00 2001
From: rakeshkky <12475069+rakeshkky@users.noreply.github.com>
Date: Tue, 2 Jun 2020 16:29:18 +0530
Subject: [PATCH 17/29] fix __typename field not resolving in Node interface

---
 server/src-lib/Hasura/GraphQL/RelaySchema.hs     |  4 ++--
 .../src-lib/Hasura/GraphQL/Resolve/Introspect.hs | 14 +++++++++-----
 server/src-lib/Hasura/GraphQL/Validate/Types.hs  | 16 ++++++++++++----
 3 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/server/src-lib/Hasura/GraphQL/RelaySchema.hs b/server/src-lib/Hasura/GraphQL/RelaySchema.hs
index d24cf542977ca..6a2133b136dd5 100644
--- a/server/src-lib/Hasura/GraphQL/RelaySchema.hs
+++ b/server/src-lib/Hasura/GraphQL/RelaySchema.hs
@@ -27,7 +27,7 @@ import           Hasura.GraphQL.Schema.Select
 mkNodeInterface :: [QualifiedTable] -> IFaceTyInfo
 mkNodeInterface relayTableNames =
   let description = G.Description "An object with globally unique ID"
-  in IFaceTyInfo (Just description) nodeType (mapFromL _fiName [idField]) $
+  in mkIFaceTyInfo (Just description) nodeType (mapFromL _fiName [idField]) $
      Set.fromList $ map mkTableTy relayTableNames
   where
     idField =
@@ -214,7 +214,7 @@ mkRelayTyAggRole tn descM insPermM selPermM updColsM delPermM pkeyCols constrain
     scalars = selByPkScalarSet <> funcArgScalarSet <> computedFieldFuncArgScalars
 
     selFldsM = snd <$> selPermM
-    selColNamesM = (map pgiName . getPGColumnFields) <$> selFldsM
+    selColNamesM = map pgiName . getPGColumnFields <$> selFldsM
     selColInpTyM = mkSelColumnTy tn <$> selColNamesM
     -- boolexp input type
     boolExpInpObjM = case selFldsM of
diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Introspect.hs b/server/src-lib/Hasura/GraphQL/Resolve/Introspect.hs
index 81d349442755d..75627cf907748 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Introspect.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Introspect.hs
@@ -146,20 +146,24 @@ ifaceR'
   => IFaceTyInfo
   -> Field
   -> m J.Object
-ifaceR' i@(IFaceTyInfo descM n flds _) fld = do
+ifaceR' ifaceTyInfo fld = do
   dummyReadIncludeDeprecated fld
   withSubFields (_fSelSet fld) $ \subFld ->
     case _fName subFld of
       "__typename"    -> retJT "__Type"
       "kind"          -> retJ TKINTERFACE
-      "name"          -> retJ $ namedTyToTxt n
-      "description"   -> retJ $ fmap G.unDescription descM
+      "name"          -> retJ $ namedTyToTxt name
+      "description"   -> retJ $ fmap G.unDescription maybeDescription
       "fields"        -> fmap J.toJSON $ mapM (`fieldR` subFld) $
                         sortOn _fiName $
-                        filter notBuiltinFld $ Map.elems flds
+                        filter notBuiltinFld $ Map.elems fields
       "possibleTypes" -> fmap J.toJSON $ mapM (`objectTypeR` subFld)
-                         =<< getImplTypes (AOTIFace i)
+                         =<< getImplTypes (AOTIFace ifaceTyInfo)
       _               -> return J.Null
+  where
+    maybeDescription = _ifDesc ifaceTyInfo
+    name = _ifName ifaceTyInfo
+    fields = _ifFields ifaceTyInfo
 
 -- 4.5.2.5
 enumTypeR
diff --git a/server/src-lib/Hasura/GraphQL/Validate/Types.hs b/server/src-lib/Hasura/GraphQL/Validate/Types.hs
index 55fb217841753..5ff241e3e9b2e 100644
--- a/server/src-lib/Hasura/GraphQL/Validate/Types.hs
+++ b/server/src-lib/Hasura/GraphQL/Validate/Types.hs
@@ -18,7 +18,15 @@ module Hasura.GraphQL.Validate.Types
   , mkObjTyInfo
   , mkHsraObjTyInfo
 
-  , IFaceTyInfo(..)
+  -- Don't expose 'IFaceTyInfo' constructor. Instead use 'mkIFaceTyInfo'
+  -- which will auto-insert the compulsory '__typename' field.
+  , IFaceTyInfo
+  , _ifDesc
+  , _ifName
+  , _ifFields
+  , _ifMemberTypes
+  , mkIFaceTyInfo
+
   , IFacesSet
   , UnionTyInfo(..)
   , FragDef(..)
@@ -277,8 +285,8 @@ mkHsraObjTyInfo descM ty implIFaces flds =
 
 mkIFaceTyInfo
   :: Maybe G.Description -> G.NamedType
-  -> Map.HashMap G.Name ObjFldInfo -> TypeLoc -> MemberTypes -> IFaceTyInfo
-mkIFaceTyInfo descM ty flds _ =
+  -> Map.HashMap G.Name ObjFldInfo -> MemberTypes -> IFaceTyInfo
+mkIFaceTyInfo descM ty flds =
   IFaceTyInfo descM ty $ Map.insert (_fiName newFld) newFld flds
   where
     newFld = typenameFld
@@ -317,7 +325,7 @@ instance Semigroup IFaceTyInfo where
 fromIFaceDef
   :: InterfaceImplementations -> G.InterfaceTypeDefinition -> TypeLoc -> IFaceTyInfo
 fromIFaceDef interfaceImplementations (G.InterfaceTypeDefinition descM n _ flds) loc =
-  mkIFaceTyInfo descM (G.NamedType n) fldMap loc implementations
+  mkIFaceTyInfo descM (G.NamedType n) fldMap implementations
   where
     fldMap = Map.fromList [(G._fldName fld, fromFldDef fld loc) | fld <- flds]
     implementations = fromMaybe mempty $ Map.lookup (G.NamedType n) interfaceImplementations

From 145975463926556f4ce256805b65b0fbbe04b3b5 Mon Sep 17 00:00:00 2001
From: rakeshkky <12475069+rakeshkky@users.noreply.github.com>
Date: Wed, 3 Jun 2020 16:10:20 +0530
Subject: [PATCH 18/29] add relay pytests

---
 .../src-lib/Hasura/GraphQL/Resolve/Select.hs  |  13 +-
 .../src-lib/Hasura/RQL/DML/Select/Internal.hs |  75 ++++++----
 server/src-lib/Hasura/RQL/DML/Select/Types.hs |   1 +
 server/src-lib/Hasura/SQL/DML.hs              |   3 +
 .../backward/page_1.yaml                      |  49 +++++++
 .../backward/page_2.yaml                      |  45 ++++++
 .../backward/page_3.yaml                      |  40 ++++++
 .../forward/page_1.yaml                       |  49 +++++++
 .../forward/page_2.yaml                       |  45 ++++++
 .../forward/page_3.yaml                       |  40 ++++++
 .../backward/page_1.yaml                      |  44 ++++++
 .../backward/page_2.yaml                      |  51 +++++++
 .../backward/page_3.yaml                      |  45 ++++++
 .../forward/page_1.yaml                       |  50 +++++++
 .../forward/page_2.yaml                       |  51 +++++++
 .../relay/basic/article_connection.yaml       |  86 ++++++++++++
 .../relay/basic/author_connection.yaml        | 128 ++++++++++++++++++
 .../relay/basic/invalid_node_id.yaml          |  19 +++
 .../graphql_query/relay/basic/node.yaml       |  67 +++++++++
 .../relay/basic/only_pageinfo.yaml            |  46 +++++++
 .../pagination_errors/after_and_before.yaml   |  21 +++
 .../pagination_errors/first_and_last.yaml     |  21 +++
 .../queries/graphql_query/relay/setup.yaml    |  79 +++++++++++
 .../queries/graphql_query/relay/teardown.yaml |   8 ++
 server/tests-py/test_graphql_queries.py       |  53 ++++++++
 server/tests-py/validate.py                   |   4 +-
 26 files changed, 1102 insertions(+), 31 deletions(-)
 create mode 100644 server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/backward/page_1.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/backward/page_2.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/backward/page_3.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/forward/page_1.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/forward/page_2.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/forward/page_3.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/backward/page_1.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/backward/page_2.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/backward/page_3.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/forward/page_1.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/forward/page_2.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/basic/article_connection.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/basic/author_connection.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/basic/invalid_node_id.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/basic/node.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/basic/only_pageinfo.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/pagination_errors/after_and_before.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/pagination_errors/first_and_last.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/setup.yaml
 create mode 100644 server/tests-py/queries/graphql_query/relay/teardown.yaml

diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Select.hs b/server/src-lib/Hasura/GraphQL/Resolve/Select.hs
index 4f7db67b62b3b..476e35876c402 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Select.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Select.hs
@@ -13,7 +13,7 @@ module Hasura.GraphQL.Resolve.Select
   , AnnSimpleSelect
   ) where
 
-import           Control.Lens                         ((^?), _2)
+import           Control.Lens                         (to, (^..), (^?), _2)
 import           Data.Has
 import           Data.Parser.JSONPath
 import           Hasura.Prelude
@@ -563,12 +563,21 @@ parseConnectionArgs pKeyColumns args = do
     (Just v, Nothing)  -> fmap ((RS.CSKAfter,) . base64Decode) <$> asPGColTextM v
     (Nothing, Just v)  -> fmap ((RS.CSKBefore,) . base64Decode) <$> asPGColTextM v
 
-  let ordByExpM = NE.nonEmpty =<< ordByExpML
+  let ordByExpM = NE.nonEmpty =<< appendPrimaryKeyOrderBy <$> ordByExpML
       tableArgs = RS.SelectArgs whereExpM ordByExpM Nothing Nothing Nothing
 
   split <- mapM (uncurry (validateConnectionSplit ordByExpM)) maybeSplit
   pure (tableArgs, slice, split)
   where
+    appendPrimaryKeyOrderBy :: [RS.AnnOrderByItemG v] -> [RS.AnnOrderByItemG v]
+    appendPrimaryKeyOrderBy orderBys =
+      let orderByColumnNames =
+            orderBys ^.. traverse . to obiColumn . RS._AOCColumn . to pgiColumn
+          pkeyOrderBys = flip mapMaybe (toList pKeyColumns) $ \pgColumnInfo ->
+                         if pgiColumn pgColumnInfo `elem` orderByColumnNames then Nothing
+                         else Just $ OrderByItemG Nothing (RS.AOCColumn pgColumnInfo) Nothing
+      in orderBys <> pkeyOrderBys
+
     validateConnectionSplit
       :: Maybe (NonEmpty (RS.AnnOrderByItemG UnresolvedVal))
       -> RS.ConnectionSplitKind
diff --git a/server/src-lib/Hasura/RQL/DML/Select/Internal.hs b/server/src-lib/Hasura/RQL/DML/Select/Internal.hs
index a08ab1914425c..89bf7221925ab 100644
--- a/server/src-lib/Hasura/RQL/DML/Select/Internal.hs
+++ b/server/src-lib/Hasura/RQL/DML/Select/Internal.hs
@@ -226,6 +226,12 @@ withJsonBuildObj parAls exps =
   where
     jsonRow = S.applyJsonBuildObj exps
 
+-- | Forces aggregation
+withForceAggregation :: S.TypeAnn -> S.SQLExp -> S.SQLExp
+withForceAggregation tyAnn e =
+  -- bool_or to force aggregation
+  S.SEFnApp "coalesce" [e, S.SETyAnn (S.SEUnsafe "bool_or('true')") tyAnn] Nothing
+
 mkAggregateOrderByExtractorAndFields
   :: AnnAggregateOrderBy -> (S.Extractor, AggregateFields)
 mkAggregateOrderByExtractorAndFields annAggOrderBy =
@@ -454,9 +460,7 @@ processAnnAggregateSelect sourcePrefixes fieldAlias annAggSel = do
              )
       TAFExp e ->
         pure ( []
-             -- bool_or to force aggregation
-             , S.SEFnApp "coalesce"
-               [ S.SELit e , S.SEUnsafe "bool_or('true')::text"] Nothing
+             , withForceAggregation S.textTypeAnn $ S.SELit e
              )
 
   let topLevelExtractor =
@@ -1019,10 +1023,15 @@ mkPrimaryKeyColumnsObjectExp sourcePrefix primaryKeyColumns =
     ]
 
 encodeBase64 :: S.SQLExp -> S.SQLExp
-encodeBase64 t =
-  S.SEFnApp "encode"
-  [S.SEFnApp "convert_to" [t, S.SELit "UTF8"] Nothing, S.SELit "base64"]
-  Nothing
+encodeBase64 =
+  removeNewline . bytesToBase64Text . convertToBytes
+  where
+    convertToBytes e =
+      S.SEFnApp "convert_to" [e, S.SELit "UTF8"] Nothing
+    bytesToBase64Text e =
+      S.SEFnApp "encode" [e, S.SELit "base64"] Nothing
+    removeNewline e =
+      S.SEFnApp "regexp_replace" [e, S.SELit "\\n", S.SELit "", S.SELit "g"] Nothing
 
 
 processConnectionSelect
@@ -1054,14 +1063,14 @@ processConnectionSelect sourcePrefixes fieldAlias relAlias colMapping connection
   (topExtractorExp, exps) <- flip runStateT [] $ processFields orderByExp
   let topExtractor = S.Extractor topExtractorExp $ Just $ S.Alias fieldIden
       allExtractors = HM.fromList $ cursorExtractors <> exps <> orderByAndDistinctExtrs
-      arrayConnectionSource = ArrayConnectionSource relAlias
-                              colMapping splitBoolExp slice selectSource
+      arrayConnectionSource = ArrayConnectionSource relAlias colMapping
+                              (mkSplitBoolExp <$> maybeSplit) maybeSlice selectSource
   pure ( arrayConnectionSource
        , topExtractor
        , allExtractors
        )
   where
-    ConnectionSelect primaryKeyColumns split slice select = connectionSelect
+    ConnectionSelect primaryKeyColumns maybeSplit maybeSlice select = connectionSelect
     AnnSelectG fields selectFrom tablePermissions tableArgs _ = select
     fieldIden = toIden fieldAlias
     thisPrefix = _pfThis sourcePrefixes
@@ -1075,18 +1084,28 @@ processConnectionSelect sourcePrefixes fieldAlias relAlias colMapping connection
            , S.mkQIdenExp (mkBaseTableAlias thisPrefix) pgColumn
            )
 
-    splitBoolExp = flip fmap split $ \splits ->
-      foldr (S.BEBin S.OrOp) (S.BELit False) $
-      flip map (toList splits) $ \s ->
-        let ConnectionSplit kind v (OrderByItemG obTyM obCol _) = s
-            obAlias = mkAnnOrderByAlias thisPrefix fieldAlias similarArrayFields obCol
-            obTy = maybe S.OTAsc unOrderType obTyM
-            compareOp = case (kind, obTy) of
-              (CSKAfter, S.OTAsc)   -> S.SGT
-              (CSKAfter, S.OTDesc)  -> S.SLT
-              (CSKBefore, S.OTAsc)  -> S.SLT
-              (CSKBefore, S.OTDesc) -> S.SGT
-        in S.BECompare compareOp (S.SEIden $ toIden obAlias) v
+    mkSplitBoolExp (firstSplit NE.:| rest) =
+      S.BEBin S.OrOp (mkSplitCompareExp firstSplit) $ mkBoolExpFromRest firstSplit rest
+      where
+        mkBoolExpFromRest previousSplit =
+          S.BEBin S.AndOp (mkEqualityCompareExp previousSplit) . \case
+            []                         -> S.BELit False
+            (thisSplit:remainingSplit) -> mkSplitBoolExp (thisSplit NE.:| remainingSplit)
+
+        mkSplitCompareExp (ConnectionSplit kind v (OrderByItemG obTyM obCol _)) =
+          let obAlias = mkAnnOrderByAlias thisPrefix fieldAlias similarArrayFields obCol
+              obTy = maybe S.OTAsc unOrderType obTyM
+              compareOp = case (kind, obTy) of
+                (CSKAfter, S.OTAsc)   -> S.SGT
+                (CSKAfter, S.OTDesc)  -> S.SLT
+                (CSKBefore, S.OTAsc)  -> S.SLT
+                (CSKBefore, S.OTDesc) -> S.SGT
+          in S.BECompare compareOp (S.SEIden $ toIden obAlias) v
+
+        mkEqualityCompareExp (ConnectionSplit _ v orderByItem) =
+          let obAlias = mkAnnOrderByAlias thisPrefix fieldAlias similarArrayFields $
+                        obiColumn orderByItem
+          in S.BECompare S.SEQ (S.SEIden $ toIden obAlias) v
 
     similarArrayFields = HM.unions $
       flip map (map snd fields) $ \case
@@ -1114,7 +1133,7 @@ processConnectionSelect sourcePrefixes fieldAlias relAlias colMapping connection
       forM fields $
         \(FieldName fieldText, field) -> (S.SELit fieldText:) . pure <$>
         case field of
-          ConnectionTypename t              -> pure $ S.SELit t
+          ConnectionTypename t              -> pure $ withForceAggregation S.textTypeAnn $ S.SELit t
           ConnectionPageInfo pageInfoFields -> pure $ processPageInfoFields pageInfoFields
           ConnectionEdges edges ->
             fmap (flip mkSimpleJsonAgg orderByExp . S.applyJsonBuildObj . concat) $ forM edges $
@@ -1133,14 +1152,14 @@ processConnectionSelect sourcePrefixes fieldAlias relAlias colMapping connection
     processPageInfoFields infoFields =
       S.applyJsonBuildObj $ flip concatMap infoFields $
       \(FieldName fieldText, field) -> (:) (S.SELit fieldText) $ pure case field of
-        PageInfoTypename t      -> S.SELit t
-        PageInfoHasNextPage     ->
+        PageInfoTypename t      -> withForceAggregation S.textTypeAnn $ S.SELit t
+        PageInfoHasNextPage     -> withForceAggregation S.boolTypeAnn $
           mkSingleFieldSelect (S.SEIden hasNextPageIden) pageInfoSelectAliasIden
-        PageInfoHasPreviousPage ->
+        PageInfoHasPreviousPage -> withForceAggregation S.boolTypeAnn $
           mkSingleFieldSelect (S.SEIden hasPreviousPageIden) pageInfoSelectAliasIden
-        PageInfoStartCursor     ->
+        PageInfoStartCursor     -> withForceAggregation S.textTypeAnn $
           encodeBase64 $ mkSingleFieldSelect (S.SEIden startCursorIden) cursorsSelectAliasIden
-        PageInfoEndCursor       ->
+        PageInfoEndCursor       -> withForceAggregation S.textTypeAnn $
           encodeBase64 $ mkSingleFieldSelect (S.SEIden endCursorIden) cursorsSelectAliasIden
       where
         mkSingleFieldSelect field fromIden = S.SESelect
diff --git a/server/src-lib/Hasura/RQL/DML/Select/Types.hs b/server/src-lib/Hasura/RQL/DML/Select/Types.hs
index a5527cba64256..d89a20ff76aa9 100644
--- a/server/src-lib/Hasura/RQL/DML/Select/Types.hs
+++ b/server/src-lib/Hasura/RQL/DML/Select/Types.hs
@@ -593,3 +593,4 @@ data PermissionLimitSubQuery
 
 $(makeLenses ''AnnSelectG)
 $(makePrisms ''AnnFieldG)
+$(makePrisms ''AnnOrderByElementG)
diff --git a/server/src-lib/Hasura/SQL/DML.hs b/server/src-lib/Hasura/SQL/DML.hs
index 08c550a56d5ef..c9b78458a7e86 100644
--- a/server/src-lib/Hasura/SQL/DML.hs
+++ b/server/src-lib/Hasura/SQL/DML.hs
@@ -272,6 +272,9 @@ jsonTypeAnn = mkTypeAnn $ PGTypeScalar PGJSON
 jsonbTypeAnn :: TypeAnn
 jsonbTypeAnn = mkTypeAnn $ PGTypeScalar PGJSONB
 
+boolTypeAnn :: TypeAnn
+boolTypeAnn = mkTypeAnn $ PGTypeScalar PGBoolean
+
 data CountType
   = CTStar
   | CTSimple ![PGCol]
diff --git a/server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/backward/page_1.yaml b/server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/backward/page_1.yaml
new file mode 100644
index 0000000000000..b64f95d0ac605
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/backward/page_1.yaml
@@ -0,0 +1,49 @@
+description: Get last page of articles with 3 items
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      article_connection(
+        last: 3
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            title
+            content
+            author_id
+          }
+        }
+      }
+    }
+response:
+  data:
+    article_connection:
+      pageInfo:
+        startCursor: eyJpZCIgOiA0fQ==
+        endCursor: eyJpZCIgOiA2fQ==
+        hasPreviousPage: true
+        hasNextPage: false
+      edges:
+      - cursor: eyJpZCIgOiA0fQ==
+        node:
+          title: Article 4
+          content: Sample article content 4
+          author_id: 2
+      - cursor: eyJpZCIgOiA1fQ==
+        node:
+          title: Article 5
+          content: Sample article content 5
+          author_id: 2
+      - cursor: eyJpZCIgOiA2fQ==
+        node:
+          title: Article 6
+          content: Sample article content 6
+          author_id: 3
diff --git a/server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/backward/page_2.yaml b/server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/backward/page_2.yaml
new file mode 100644
index 0000000000000..29b9c89a62b6d
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/backward/page_2.yaml
@@ -0,0 +1,45 @@
+description: Get last page of articles with 2 items before 'Article 4'
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      article_connection(
+        last: 2
+        before: "eyJpZCIgOiA0fQ=="
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            title
+            content
+            author_id
+          }
+        }
+      }
+    }
+response:
+  data:
+    article_connection:
+      pageInfo:
+        startCursor: eyJpZCIgOiAyfQ==
+        endCursor: eyJpZCIgOiAzfQ==
+        hasPreviousPage: true
+        hasNextPage: true
+      edges:
+      - cursor: eyJpZCIgOiAyfQ==
+        node:
+          title: Article 2
+          content: Sample article content 2
+          author_id: 1
+      - cursor: eyJpZCIgOiAzfQ==
+        node:
+          title: Article 3
+          content: Sample article content 3
+          author_id: 1
diff --git a/server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/backward/page_3.yaml b/server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/backward/page_3.yaml
new file mode 100644
index 0000000000000..22a75403f7192
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/backward/page_3.yaml
@@ -0,0 +1,40 @@
+description: Get last page of articles before 'Article 2'
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      article_connection(
+        last: 2
+        before: "eyJpZCIgOiAyfQ=="
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            title
+            content
+            author_id
+          }
+        }
+      }
+    }
+response:
+  data:
+    article_connection:
+      pageInfo:
+        startCursor: eyJpZCIgOiAxfQ==
+        endCursor: eyJpZCIgOiAxfQ==
+        hasPreviousPage: false
+        hasNextPage: true
+      edges:
+      - cursor: eyJpZCIgOiAxfQ==
+        node:
+          title: Article 1
+          content: Sample article content 1
+          author_id: 1
diff --git a/server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/forward/page_1.yaml b/server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/forward/page_1.yaml
new file mode 100644
index 0000000000000..91d3c5637e21f
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/forward/page_1.yaml
@@ -0,0 +1,49 @@
+description: Get 1st page of articles with 3 items
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      article_connection(
+        first: 3
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            title
+            content
+            author_id
+          }
+        }
+      }
+    }
+response:
+  data:
+    article_connection:
+      pageInfo:
+        startCursor: eyJpZCIgOiAxfQ==
+        endCursor: eyJpZCIgOiAzfQ==
+        hasPreviousPage: false
+        hasNextPage: true
+      edges:
+      - cursor: eyJpZCIgOiAxfQ==
+        node:
+          title: Article 1
+          content: Sample article content 1
+          author_id: 1
+      - cursor: eyJpZCIgOiAyfQ==
+        node:
+          title: Article 2
+          content: Sample article content 2
+          author_id: 1
+      - cursor: eyJpZCIgOiAzfQ==
+        node:
+          title: Article 3
+          content: Sample article content 3
+          author_id: 1
diff --git a/server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/forward/page_2.yaml b/server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/forward/page_2.yaml
new file mode 100644
index 0000000000000..7814e65e4f316
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/forward/page_2.yaml
@@ -0,0 +1,45 @@
+description: Get 2nd page of articles with 2 items
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      article_connection(
+        first: 2
+        after: "eyJpZCIgOiAzfQ=="
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            title
+            content
+            author_id
+          }
+        }
+      }
+    }
+response:
+  data:
+    article_connection:
+      pageInfo:
+        startCursor: eyJpZCIgOiA0fQ==
+        endCursor: eyJpZCIgOiA1fQ==
+        hasPreviousPage: true
+        hasNextPage: true
+      edges:
+      - cursor: eyJpZCIgOiA0fQ==
+        node:
+          title: Article 4
+          content: Sample article content 4
+          author_id: 2
+      - cursor: eyJpZCIgOiA1fQ==
+        node:
+          title: Article 5
+          content: Sample article content 5
+          author_id: 2
diff --git a/server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/forward/page_3.yaml b/server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/forward/page_3.yaml
new file mode 100644
index 0000000000000..4b91442a00299
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/article_pagination_no_orderby/forward/page_3.yaml
@@ -0,0 +1,40 @@
+description: Get 3rd page of articles
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      article_connection(
+        first: 3
+        after: "eyJpZCIgOiA1fQ=="
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            title
+            content
+            author_id
+          }
+        }
+      }
+    }
+response:
+  data:
+    article_connection:
+      pageInfo:
+        startCursor: eyJpZCIgOiA2fQ==
+        endCursor: eyJpZCIgOiA2fQ==
+        hasPreviousPage: true
+        hasNextPage: false
+      edges:
+      - cursor: eyJpZCIgOiA2fQ==
+        node:
+          title: Article 6
+          content: Sample article content 6
+          author_id: 3
diff --git a/server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/backward/page_1.yaml b/server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/backward/page_1.yaml
new file mode 100644
index 0000000000000..ee0d0b66c2bd8
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/backward/page_1.yaml
@@ -0,0 +1,44 @@
+description: Fetch 1st page from last of articles ordered by their article count
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      author_connection(
+        last: 1
+        order_by: {articles_aggregate: {count: asc}}
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            name
+            articles_aggregate{
+              aggregate{
+                count
+              }
+            }
+          }
+        }
+      }
+    }
+response:
+  data:
+    author_connection:
+      pageInfo:
+        startCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAzfSwgImlkIiA6IDF9
+        endCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAzfSwgImlkIiA6IDF9
+        hasPreviousPage: true
+        hasNextPage: false
+      edges:
+      - cursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAzfSwgImlkIiA6IDF9
+        node:
+          name: Author 1
+          articles_aggregate:
+            aggregate:
+              count: 3
diff --git a/server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/backward/page_2.yaml b/server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/backward/page_2.yaml
new file mode 100644
index 0000000000000..6e72d8c29accd
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/backward/page_2.yaml
@@ -0,0 +1,51 @@
+description: Fetch 2nd page from last of articles ordered by their article count
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      author_connection(
+        last: 2
+        order_by: {articles_aggregate: {count: asc}}
+        before: "eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAzfSwgImlkIiA6IDF9"
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            name
+            articles_aggregate{
+              aggregate{
+                count
+              }
+            }
+          }
+        }
+      }
+    }
+response:
+  data:
+    author_connection:
+      pageInfo:
+        startCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAxfSwgImlkIiA6IDN9
+        endCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAyfSwgImlkIiA6IDJ9
+        hasPreviousPage: true
+        hasNextPage: true
+      edges:
+      - cursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAxfSwgImlkIiA6IDN9
+        node:
+          name: Author 3
+          articles_aggregate:
+            aggregate:
+              count: 1
+      - cursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAyfSwgImlkIiA6IDJ9
+        node:
+          name: Author 2
+          articles_aggregate:
+            aggregate:
+              count: 2
diff --git a/server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/backward/page_3.yaml b/server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/backward/page_3.yaml
new file mode 100644
index 0000000000000..d71acbe1d0a42
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/backward/page_3.yaml
@@ -0,0 +1,45 @@
+description: Fetch 3rd page from last of articles ordered by their article count
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      author_connection(
+        last: 1
+        order_by: {articles_aggregate: {count: asc}}
+        before: "eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAxfSwgImlkIiA6IDN9"
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            name
+            articles_aggregate{
+              aggregate{
+                count
+              }
+            }
+          }
+        }
+      }
+    }
+response:
+  data:
+    author_connection:
+      pageInfo:
+        startCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAwfSwgImlkIiA6IDR9
+        endCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAwfSwgImlkIiA6IDR9
+        hasPreviousPage: false
+        hasNextPage: true
+      edges:
+      - cursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAwfSwgImlkIiA6IDR9
+        node:
+          name: Author 4
+          articles_aggregate:
+            aggregate:
+              count: 0
diff --git a/server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/forward/page_1.yaml b/server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/forward/page_1.yaml
new file mode 100644
index 0000000000000..a47b32a898c70
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/forward/page_1.yaml
@@ -0,0 +1,50 @@
+description: Fetch 1st page of articles ordered by their article count
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      author_connection(
+        first: 2
+        order_by: {articles_aggregate: {count: asc}}
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            name
+            articles_aggregate{
+              aggregate{
+                count
+              }
+            }
+          }
+        }
+      }
+    }
+response:
+  data:
+    author_connection:
+      pageInfo:
+        startCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAwfSwgImlkIiA6IDR9
+        endCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAxfSwgImlkIiA6IDN9
+        hasPreviousPage: false
+        hasNextPage: true
+      edges:
+      - cursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAwfSwgImlkIiA6IDR9
+        node:
+          name: Author 4
+          articles_aggregate:
+            aggregate:
+              count: 0
+      - cursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAxfSwgImlkIiA6IDN9
+        node:
+          name: Author 3
+          articles_aggregate:
+            aggregate:
+              count: 1
diff --git a/server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/forward/page_2.yaml b/server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/forward/page_2.yaml
new file mode 100644
index 0000000000000..196a12cd7a396
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/author_pagination_articles_aggregate_orderby/forward/page_2.yaml
@@ -0,0 +1,51 @@
+description: Fetch 2nd page of articles ordered by their article count
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      author_connection(
+        first: 2
+        order_by: {articles_aggregate: {count: asc}}
+        after: "eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAxfSwgImlkIiA6IDN9"
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        edges{
+          cursor
+          node{
+            name
+            articles_aggregate{
+              aggregate{
+                count
+              }
+            }
+          }
+        }
+      }
+    }
+response:
+  data:
+    author_connection:
+      pageInfo:
+        startCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAyfSwgImlkIiA6IDJ9
+        endCursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAzfSwgImlkIiA6IDF9
+        hasPreviousPage: true
+        hasNextPage: false
+      edges:
+      - cursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAyfSwgImlkIiA6IDJ9
+        node:
+          name: Author 2
+          articles_aggregate:
+            aggregate:
+              count: 2
+      - cursor: eyJhcnRpY2xlc19hZ2dyZWdhdGUiIDogeyJjb3VudCIgOiAzfSwgImlkIiA6IDF9
+        node:
+          name: Author 1
+          articles_aggregate:
+            aggregate:
+              count: 3
diff --git a/server/tests-py/queries/graphql_query/relay/basic/article_connection.yaml b/server/tests-py/queries/graphql_query/relay/basic/article_connection.yaml
new file mode 100644
index 0000000000000..423bcfa2aa6ba
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/basic/article_connection.yaml
@@ -0,0 +1,86 @@
+description: Query articles connection with pageInfo and edges
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      article_connection{
+        pageInfo{
+          hasNextPage
+          startCursor
+          endCursor
+          hasPreviousPage
+        }
+        edges{
+          cursor
+          node_id: node{
+            id
+          }
+          node{
+            title
+            content
+            author{
+              name
+            }
+          }
+        }
+      }
+    }
+
+response:
+  data:
+    article_connection:
+      pageInfo:
+        hasNextPage: false
+        startCursor: eyJpZCIgOiAxfQ==
+        endCursor: eyJpZCIgOiA2fQ==
+        hasPreviousPage: false
+      edges:
+      - cursor: eyJpZCIgOiAxfQ==
+        node_id:
+          id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiAxfX0=
+        node:
+          title: Article 1
+          content: Sample article content 1
+          author:
+            name: Author 1
+      - cursor: eyJpZCIgOiAyfQ==
+        node_id:
+          id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiAyfX0=
+        node:
+          title: Article 2
+          content: Sample article content 2
+          author:
+            name: Author 1
+      - cursor: eyJpZCIgOiAzfQ==
+        node_id:
+          id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiAzfX0=
+        node:
+          title: Article 3
+          content: Sample article content 3
+          author:
+            name: Author 1
+      - cursor: eyJpZCIgOiA0fQ==
+        node_id:
+          id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiA0fX0=
+        node:
+          title: Article 4
+          content: Sample article content 4
+          author:
+            name: Author 2
+      - cursor: eyJpZCIgOiA1fQ==
+        node_id:
+          id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiA1fX0=
+        node:
+          title: Article 5
+          content: Sample article content 5
+          author:
+            name: Author 2
+      - cursor: eyJpZCIgOiA2fQ==
+        node_id:
+          id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiA2fX0=
+        node:
+          title: Article 6
+          content: Sample article content 6
+          author:
+            name: Author 3
diff --git a/server/tests-py/queries/graphql_query/relay/basic/author_connection.yaml b/server/tests-py/queries/graphql_query/relay/basic/author_connection.yaml
new file mode 100644
index 0000000000000..74bb76943f79d
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/basic/author_connection.yaml
@@ -0,0 +1,128 @@
+description: Query author connection with edges
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      author_connection{
+        edges{
+          cursor
+          node{
+            id
+            name
+            articles{
+              id
+              title
+              content
+            }
+            articles_aggregate{
+              aggregate{
+                count
+              }
+            }
+            articles_connection{
+              edges{
+                cursor
+                node{
+                  id
+                  title
+                  content
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+response:
+  data:
+    author_connection:
+      edges:
+      - cursor: eyJpZCIgOiAxfQ==
+        node:
+          id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImF1dGhvciJ9LCAiY29sdW1ucyIgOiB7ImlkIiA6IDF9fQ==
+          name: Author 1
+          articles:
+          - id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiAxfX0=
+            title: Article 1
+            content: Sample article content 1
+          - id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiAyfX0=
+            title: Article 2
+            content: Sample article content 2
+          - id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiAzfX0=
+            title: Article 3
+            content: Sample article content 3
+          articles_aggregate:
+            aggregate:
+              count: 3
+          articles_connection:
+            edges:
+            - cursor: eyJpZCIgOiAxfQ==
+              node:
+                id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiAxfX0=
+                title: Article 1
+                content: Sample article content 1
+            - cursor: eyJpZCIgOiAyfQ==
+              node:
+                id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiAyfX0=
+                title: Article 2
+                content: Sample article content 2
+            - cursor: eyJpZCIgOiAzfQ==
+              node:
+                id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiAzfX0=
+                title: Article 3
+                content: Sample article content 3
+      - cursor: eyJpZCIgOiAyfQ==
+        node:
+          id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImF1dGhvciJ9LCAiY29sdW1ucyIgOiB7ImlkIiA6IDJ9fQ==
+          name: Author 2
+          articles:
+          - id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiA0fX0=
+            title: Article 4
+            content: Sample article content 4
+          - id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiA1fX0=
+            title: Article 5
+            content: Sample article content 5
+          articles_aggregate:
+            aggregate:
+              count: 2
+          articles_connection:
+            edges:
+            - cursor: eyJpZCIgOiA0fQ==
+              node:
+                id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiA0fX0=
+                title: Article 4
+                content: Sample article content 4
+            - cursor: eyJpZCIgOiA1fQ==
+              node:
+                id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiA1fX0=
+                title: Article 5
+                content: Sample article content 5
+      - cursor: eyJpZCIgOiAzfQ==
+        node:
+          id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImF1dGhvciJ9LCAiY29sdW1ucyIgOiB7ImlkIiA6IDN9fQ==
+          name: Author 3
+          articles:
+          - id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiA2fX0=
+            title: Article 6
+            content: Sample article content 6
+          articles_aggregate:
+            aggregate:
+              count: 1
+          articles_connection:
+            edges:
+            - cursor: eyJpZCIgOiA2fQ==
+              node:
+                id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiA2fX0=
+                title: Article 6
+                content: Sample article content 6
+      - cursor: eyJpZCIgOiA0fQ==
+        node:
+          id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImF1dGhvciJ9LCAiY29sdW1ucyIgOiB7ImlkIiA6IDR9fQ==
+          name: Author 4
+          articles: []
+          articles_aggregate:
+            aggregate:
+              count: 0
+          articles_connection:
+            edges: []
diff --git a/server/tests-py/queries/graphql_query/relay/basic/invalid_node_id.yaml b/server/tests-py/queries/graphql_query/relay/basic/invalid_node_id.yaml
new file mode 100644
index 0000000000000..6cd36891ce112
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/basic/invalid_node_id.yaml
@@ -0,0 +1,19 @@
+description: Query node interface with invalid node id
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      node(id: "eyJpZCIgOiA0fQ=="){
+        __typename
+        ... on author{
+          name
+        }
+      }
+    }
+response:
+  errors:
+  - extensions:
+      path: "$.selectionSet.node"
+      code: validation-failed
+    message: the node id is invalid
diff --git a/server/tests-py/queries/graphql_query/relay/basic/node.yaml b/server/tests-py/queries/graphql_query/relay/basic/node.yaml
new file mode 100644
index 0000000000000..117db4e34e117
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/basic/node.yaml
@@ -0,0 +1,67 @@
+description: Query the relay Node interface
+url: /v1/relay
+status: 200
+query:
+  variables:
+    author_id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImF1dGhvciJ9LCAiY29sdW1ucyIgOiB7ImlkIiA6IDJ9fQ==
+    article_id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImFydGljbGUifSwgImNvbHVtbnMiIDogeyJpZCIgOiAzfX0=
+  query: |
+    query nodeQuery($author_id: ID!, $article_id: ID!){
+      author_node: node(id: $author_id){
+        __typename
+        ... on author{
+          name
+          articles_connection{
+            edges{
+              cursor
+              node{
+                title
+                content
+              }
+            }
+          }
+        }
+      }
+
+      article_node_with_author_id: node(id: $author_id){
+        id
+        ... on article{
+          title
+          content
+        }
+      }
+
+      article_node: node(id: $article_id){
+        __typename
+        ... on article{
+          title
+          content
+          author{
+            name
+          }
+        }
+      }
+    }
+response:
+  data:
+    author_node:
+      __typename: author
+      name: Author 2
+      articles_connection:
+        edges:
+        - cursor: eyJpZCIgOiA0fQ==
+          node:
+            title: Article 4
+            content: Sample article content 4
+        - cursor: eyJpZCIgOiA1fQ==
+          node:
+            title: Article 5
+            content: Sample article content 5
+    article_node_with_author_id:
+      id: eyJ0YWJsZSIgOiB7InNjaGVtYSIgOiAicHVibGljIiwgIm5hbWUiIDogImF1dGhvciJ9LCAiY29sdW1ucyIgOiB7ImlkIiA6IDJ9fQ==
+    article_node:
+      __typename: article
+      title: Article 3
+      content: Sample article content 3
+      author:
+        name: Author 1
diff --git a/server/tests-py/queries/graphql_query/relay/basic/only_pageinfo.yaml b/server/tests-py/queries/graphql_query/relay/basic/only_pageinfo.yaml
new file mode 100644
index 0000000000000..d36c2769e244e
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/basic/only_pageinfo.yaml
@@ -0,0 +1,46 @@
+description: Query the article connection with only pageInfo
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      article_connection(
+        order_by: {title: asc}
+        last: 2
+      ){
+        pageInfo{
+          startCursor
+          endCursor
+          hasPreviousPage
+          hasNextPage
+        }
+        startCursor: pageInfo{
+          startCursor
+        }
+        endCursor: pageInfo{
+          endCursor
+        }
+        hasPreviousPage: pageInfo{
+          hasPreviousPage
+        }
+        hasNextPage: pageInfo{
+          hasNextPage
+        }
+      }
+    }
+response:
+  data:
+    article_connection:
+      pageInfo:
+        startCursor: eyJ0aXRsZSIgOiAiQXJ0aWNsZSA1IiwgImlkIiA6IDV9
+        endCursor: eyJ0aXRsZSIgOiAiQXJ0aWNsZSA2IiwgImlkIiA6IDZ9
+        hasPreviousPage: true
+        hasNextPage: false
+      startCursor:
+        startCursor: eyJ0aXRsZSIgOiAiQXJ0aWNsZSA1IiwgImlkIiA6IDV9
+      endCursor:
+        endCursor: eyJ0aXRsZSIgOiAiQXJ0aWNsZSA2IiwgImlkIiA6IDZ9
+      hasPreviousPage:
+        hasPreviousPage: true
+      hasNextPage:
+        hasNextPage: false
diff --git a/server/tests-py/queries/graphql_query/relay/pagination_errors/after_and_before.yaml b/server/tests-py/queries/graphql_query/relay/pagination_errors/after_and_before.yaml
new file mode 100644
index 0000000000000..7559bda0a8bb2
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/pagination_errors/after_and_before.yaml
@@ -0,0 +1,21 @@
+description: Use after and before arguments in the same query
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      author_connection(
+       after: "eyJpZCIgOiAyfQ=="
+       before: "eyJpZCIgOiA0fQ=="
+      ){
+        edges{
+          cursor
+        }
+      }
+    }
+response:
+  errors:
+  - extensions:
+      path: "$.selectionSet.author_connection"
+      code: validation-failed
+    message: '"after" and "before" are not allowed at once'
diff --git a/server/tests-py/queries/graphql_query/relay/pagination_errors/first_and_last.yaml b/server/tests-py/queries/graphql_query/relay/pagination_errors/first_and_last.yaml
new file mode 100644
index 0000000000000..9aaa729981679
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/pagination_errors/first_and_last.yaml
@@ -0,0 +1,21 @@
+description: Use first and last arguments in the same query
+url: /v1/relay
+status: 200
+query:
+  query: |
+    query {
+      author_connection(
+        first: 1
+        last: 2
+      ){
+        edges{
+          cursor
+        }
+      }
+    }
+response:
+  errors:
+  - extensions:
+      path: "$.selectionSet.author_connection"
+      code: validation-failed
+    message: '"first" and "last" are not allowed at once'
diff --git a/server/tests-py/queries/graphql_query/relay/setup.yaml b/server/tests-py/queries/graphql_query/relay/setup.yaml
new file mode 100644
index 0000000000000..44f330d7c43e8
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/setup.yaml
@@ -0,0 +1,79 @@
+type: bulk
+args:
+- type: run_sql
+  args:
+    sql: |
+      CREATE TABLE author(
+          id SERIAL PRIMARY KEY,
+          name TEXT UNIQUE NOT NULL
+      );
+
+      INSERT INTO author (name)
+      VALUES ('Author 1'), ('Author 2'), ('Author 3'), ('Author 4');
+
+      CREATE TABLE article (
+        id SERIAL PRIMARY KEY,
+        title TEXT,
+        content TEXT,
+        author_id INTEGER REFERENCES author(id)
+      );
+
+      INSERT INTO article (title, content, author_id)
+      VALUES
+      (
+        'Article 1',
+        'Sample article content 1',
+        1
+      ),
+      (
+        'Article 2',
+        'Sample article content 2',
+        1
+      ),
+      (
+        'Article 3',
+        'Sample article content 3',
+        1
+      ),
+      (
+        'Article 4',
+        'Sample article content 4',
+        2
+      ),
+      (
+        'Article 5',
+        'Sample article content 5',
+        2
+      ),
+      (
+        'Article 6',
+        'Sample article content 6',
+        3
+      );
+
+# Track tables and define relationships
+- type: track_table
+  args:
+    name: author
+    schema: public
+
+- type: track_table
+  args:
+    name: article
+    schema: public
+
+- type: create_object_relationship
+  args:
+    table: article
+    name: author
+    using:
+      foreign_key_constraint_on: author_id
+
+- type: create_array_relationship
+  args:
+    table: author
+    name: articles
+    using:
+      foreign_key_constraint_on:
+        table: article
+        column: author_id
diff --git a/server/tests-py/queries/graphql_query/relay/teardown.yaml b/server/tests-py/queries/graphql_query/relay/teardown.yaml
new file mode 100644
index 0000000000000..65471ac1d1388
--- /dev/null
+++ b/server/tests-py/queries/graphql_query/relay/teardown.yaml
@@ -0,0 +1,8 @@
+type: bulk
+args:
+- type: run_sql
+  args:
+    cascade: true
+    sql: |
+      DROP TABLE article;
+      DROP TABLE author;
diff --git a/server/tests-py/test_graphql_queries.py b/server/tests-py/test_graphql_queries.py
index 2046895e557e5..18662bc642c0c 100644
--- a/server/tests-py/test_graphql_queries.py
+++ b/server/tests-py/test_graphql_queries.py
@@ -650,3 +650,56 @@ def with_admin_secret(self, hge_ctx, f):
         resp_sql = resp_json[0]['sql']
         exp_sql = conf['response'][0]['sql']
         assert resp_sql == exp_sql, resp_json
+
+@pytest.mark.parametrize('transport', ['http', 'websocket'])
+@usefixtures('per_class_tests_db_state')
+class TestRelayQueries:
+
+    @classmethod
+    def dir(cls):
+        return 'queries/graphql_query/relay'
+
+    # Basic queries
+    def test_article_connection(self, hge_ctx, transport):
+        check_query_f(hge_ctx, self.dir() + '/basic/article_connection.yaml', transport)
+
+    def test_author_connection(self, hge_ctx, transport):
+        check_query_f(hge_ctx, self.dir() + '/basic/author_connection.yaml', transport)
+
+    def test_node(self, hge_ctx, transport):
+        check_query_f(hge_ctx, self.dir() + '/basic/node.yaml', transport)
+
+    def test_invalid_node(self, hge_ctx, transport):
+        check_query_f(hge_ctx, self.dir() + '/basic/invalid_node_id.yaml', transport)
+
+    def test_only_pageinfo(self, hge_ctx, transport):
+        check_query_f(hge_ctx, self.dir() + '/basic/only_pageinfo.yaml', transport)
+
+    # Articles forward pagination
+    def test_article_no_orderby_forward_pagination(self, hge_ctx, transport):
+        _test_relay_pagination(hge_ctx, transport, self.dir() + "/article_pagination_no_orderby/forward", 3)
+
+    # Articles backward pagination
+    def test_article_no_orderby_backward_pagination(self, hge_ctx, transport):
+        _test_relay_pagination(hge_ctx, transport, self.dir() + "/article_pagination_no_orderby/backward", 3)
+
+    # Authors forward pagination
+    def test_author_orderby_articles_aggregate_orderby_forward_pagination(self, hge_ctx, transport):
+        _test_relay_pagination(hge_ctx, transport, self.dir() + "/author_pagination_articles_aggregate_orderby/forward", 2)
+
+    # Authors backward pagination
+    def test_author_orderby_articles_aggregate_orderby_backward_pagination(self, hge_ctx, transport):
+        _test_relay_pagination(hge_ctx, transport, self.dir() + "/author_pagination_articles_aggregate_orderby/backward", 3)
+
+    # Pagination errors
+    def test_first_and_last_fail(self, hge_ctx, transport):
+        check_query_f(hge_ctx, self.dir() + "/pagination_errors/first_and_last.yaml", transport)
+
+    def test_after_and_before_fail(self, hge_ctx, transport):
+        check_query_f(hge_ctx, self.dir() + "/pagination_errors/after_and_before.yaml", transport)
+
+def _test_relay_pagination(hge_ctx, transport, test_file_prefix, no_of_pages):
+    for i in range(no_of_pages):
+        page_no = i + 1
+        test_file = "page_" + str(page_no) + ".yaml"
+        check_query_f(hge_ctx, test_file_prefix + "/" + test_file, transport)
diff --git a/server/tests-py/validate.py b/server/tests-py/validate.py
index 99553e62f56be..251eaa636e9aa 100644
--- a/server/tests-py/validate.py
+++ b/server/tests-py/validate.py
@@ -211,7 +211,7 @@ def check_query(hge_ctx, conf, transport='http', add_auth=True, claims_namespace
 
 def validate_gql_ws_q(hge_ctx, conf, headers, retry=False, via_subscription=False):
     assert 'response' in conf
-    assert conf['url'].endswith('/graphql')
+    assert conf['url'].endswith('/graphql') or conf['url'].endswith('/relay')
     endpoint = conf['url']
     query = conf['query']
     exp_http_response = conf['response']
@@ -226,6 +226,8 @@ def validate_gql_ws_q(hge_ctx, conf, headers, retry=False, via_subscription=Fals
 
     if endpoint == '/v1alpha1/graphql':
         ws_client = GQLWsClient(hge_ctx, '/v1alpha1/graphql')
+    elif endpoint == '/v1/relay':
+        ws_client = GQLWsClient(hge_ctx, '/v1/relay')
     else:
         ws_client = hge_ctx.ws_client
     print(ws_client.ws_url)

From 3cc4a1dc55b6295f959bde66eb04c9691283e79e Mon Sep 17 00:00:00 2001
From: rakeshkky <12475069+rakeshkky@users.noreply.github.com>
Date: Wed, 3 Jun 2020 17:31:25 +0530
Subject: [PATCH 19/29] fix relay tests if any authorization set

---
 server/tests-py/validate.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/server/tests-py/validate.py b/server/tests-py/validate.py
index 251eaa636e9aa..bbc6369df8a80 100644
--- a/server/tests-py/validate.py
+++ b/server/tests-py/validate.py
@@ -65,7 +65,7 @@ def check_event(hge_ctx, evts_webhook, trig_name, table, operation, exp_ev_data,
 
 
 def test_forbidden_when_admin_secret_reqd(hge_ctx, conf):
-    if conf['url'] == '/v1/graphql':
+    if conf['url'] == '/v1/graphql' or conf['url'] == '/v1/relay':
         if conf['status'] == 404:
             status = [404]
         else:
@@ -104,7 +104,7 @@ def test_forbidden_when_admin_secret_reqd(hge_ctx, conf):
 
 
 def test_forbidden_webhook(hge_ctx, conf):
-    if conf['url'] == '/v1/graphql':
+    if conf['url'] == '/v1/graphql' or conf['url'] == '/v1/relay':
         if conf['status'] == 404:
             status = [404]
         else:

From ed107c3db295dba499a56f0a9be59cc7fb59a1d1 Mon Sep 17 00:00:00 2001
From: rakeshkky <12475069+rakeshkky@users.noreply.github.com>
Date: Thu, 4 Jun 2020 08:56:41 +0530
Subject: [PATCH 20/29] update CHANGELOG.md

---
 CHANGELOG.md | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a8bb2d7747936..ded855b515a9c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,14 @@
 
 ## Next release
 
+### Relay
+
+The Hasura GraphQL Engine serves [Relay](https://relay.dev/en/) schema for Postgres tables which has a primary key defined.
+
+The Relay schema can be accessed through `/v1/relay` endpoint.
+
+[Add docs links][add console screenshot for relay toggle]
+
 ### Remote Joins
 
 Remote Joins extend the concept of joining data across tables, to being able to join data across tables and remote schemas.
@@ -291,7 +299,7 @@ For example, see [here](https://hasura.io/docs/1.0/graphql/manual/api-reference/
 - console: prevent trailing spaces while creating new role (close #3871) (#4497)
 - docs: add API docs for using environment variables as webhook urls in event triggers
 - server: fix recreating action's permissions (close #4377)
-- server: make the graceful shutdown logic customizable (graceful shutdown on the SIGTERM signal continues to be the default) 
+- server: make the graceful shutdown logic customizable (graceful shutdown on the SIGTERM signal continues to be the default)
 - docs: add reference docs for CLI (clsoe #4327) (#4408)
 
 ## `v1.2.0-beta.4`

From a737c0829bbb80e9ab0e20495e5613e66772cafa Mon Sep 17 00:00:00 2001
From: rakeshkky <12475069+rakeshkky@users.noreply.github.com>
Date: Thu, 4 Jun 2020 09:30:46 +0530
Subject: [PATCH 21/29] remove unused import warning

---
 server/src-lib/Hasura/GraphQL/Resolve/Action.hs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/server/src-lib/Hasura/GraphQL/Resolve/Action.hs b/server/src-lib/Hasura/GraphQL/Resolve/Action.hs
index a51cb9e38ef1d..524c2936042c3 100644
--- a/server/src-lib/Hasura/GraphQL/Resolve/Action.hs
+++ b/server/src-lib/Hasura/GraphQL/Resolve/Action.hs
@@ -43,7 +43,6 @@ import           Hasura.GraphQL.Resolve.Context
 import           Hasura.GraphQL.Resolve.InputValue
 import           Hasura.GraphQL.Resolve.Select        (processTableSelectionSet)
 import           Hasura.GraphQL.Validate.SelectionSet
-import           Hasura.GraphQL.Validate.Types
 import           Hasura.HTTP
 import           Hasura.RQL.DDL.Headers               (makeHeadersFromConf, toHeadersConf)
 import           Hasura.RQL.DDL.Schema.Cache

From e7cd5a531c62d0eda1fa16830fc168cd7575490d Mon Sep 17 00:00:00 2001
From: rakeshkky <12475069+rakeshkky@users.noreply.github.com>
Date: Thu, 4 Jun 2020 10:01:06 +0530
Subject: [PATCH 22/29] fix array relation connection field type & minor no-op
 refactor

---
 .../src-lib/Hasura/GraphQL/Schema/Select.hs   | 65 ++++++++++---------
 1 file changed, 35 insertions(+), 30 deletions(-)

diff --git a/server/src-lib/Hasura/GraphQL/Schema/Select.hs b/server/src-lib/Hasura/GraphQL/Schema/Select.hs
index 1ccc8ebb0b0bd..afb6c60fe2840 100644
--- a/server/src-lib/Hasura/GraphQL/Schema/Select.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/Select.hs
@@ -172,9 +172,10 @@ mkRelationshipField
   -> Maybe (NonEmpty PGColumnInfo)
   -> Bool
   -> [ObjFldInfo]
-mkRelationshipField allowAgg (RelInfo rn rTy _ remTab isManual) isRelay maybePkCols isNullable = case rTy of
-  ArrRel -> bool [arrRelFld] ([arrRelFld, aggArrRelFld] <> connFields) allowAgg
-  ObjRel -> [objRelFld]
+mkRelationshipField allowAgg (RelInfo rn rTy _ remTab isManual) isRelay maybePkCols isNullable =
+  case rTy of
+    ArrRel -> bool [arrRelFld] ([arrRelFld, aggArrRelFld] <> connFields) allowAgg
+    ObjRel -> [objRelFld]
   where
     objRelFld = mkHsraObjFldInfo (Just "An object relationship")
       (mkRelName rn) Map.empty objRelTy
@@ -187,16 +188,29 @@ mkRelationshipField allowAgg (RelInfo rn rTy _ remTab isManual) isRelay maybePkC
       (fromInpValL $ mkSelArgs remTab) $
       G.toGT $ G.toNT $ G.toLT $ G.toNT $ mkTableTy remTab
 
-    arrConnectionFld = if isNothing maybePkCols then [] else pure $
+    connFields = if isNothing maybePkCols || not isRelay then [] else pure $
       mkHsraObjFldInfo Nothing (mkConnectionRelName rn)
       (fromInpValL $ mkConnectionArgs remTab) $
-      G.toGT $ G.toNT $ G.toLT $ G.toNT $ mkTableConnectionTy remTab
+      G.toGT $ G.toNT $ mkTableConnectionTy remTab
 
     aggArrRelFld = mkHsraObjFldInfo (Just "An aggregated array relationship")
       (mkAggRelName rn) (fromInpValL $ mkSelArgs remTab) $
       G.toGT $ G.toNT $ mkTableAggTy remTab
 
-    connFields = bool [] arrConnectionFld isRelay
+mkTableObjectDescription :: QualifiedTable -> Maybe PGDescription -> G.Description
+mkTableObjectDescription tn pgDescription =
+  mkDescriptionWith pgDescription $ "columns and relationships of " <>> tn
+
+mkTableObjectFields :: Bool -> [SelField] -> [ObjFldInfo]
+mkTableObjectFields isRelay =
+  concatMap \case
+    SFPGColumn info -> pure $ mkPGColFld info
+    SFRelationship info -> mkRelationshipField' info
+    SFComputedField info -> pure $ mkComputedFieldFld info
+    SFRemoteRelationship info -> pure $ mkRemoteRelationshipFld info
+  where
+    mkRelationshipField' (RelationshipFieldInfo relInfo allowAgg _ _ _ maybePkCols isNullable) =
+      mkRelationshipField allowAgg relInfo isRelay maybePkCols isNullable
 
 {-
 type table {
@@ -211,39 +225,30 @@ mkTableObj
   -> Maybe PGDescription
   -> [SelField]
   -> ObjTyInfo
-mkTableObj tn descM allowedFlds =
-  mkObjTyInfo (Just desc) (mkTableTy tn) Set.empty (mapFromL _fiName flds) TLHasuraType
+mkTableObj tn descM allowedFields =
+  mkObjTyInfo (Just desc) (mkTableTy tn) Set.empty (mapFromL _fiName fields) TLHasuraType
   where
-    flds = flip concatMap allowedFlds $ \case
-      SFPGColumn info -> pure $ mkPGColFld info
-      SFRelationship info -> mkRelationshipField' info
-      SFComputedField info -> pure $ mkComputedFieldFld info
-      SFRemoteRelationship info -> pure $ mkRemoteRelationshipFld info
-
-    mkRelationshipField' (RelationshipFieldInfo relInfo allowAgg _ _ _ maybePkCols isNullable) =
-      mkRelationshipField allowAgg relInfo False maybePkCols isNullable
-    desc = mkDescriptionWith descM $ "columns and relationships of " <>> tn
+    fields = mkTableObjectFields False allowedFields
+    desc = mkTableObjectDescription tn descM
 
 mkRelayTableObj
   :: QualifiedTable
   -> Maybe PGDescription
   -> [SelField]
   -> ObjTyInfo
-mkRelayTableObj tn descM allowedFlds =
-  mkObjTyInfo (Just desc) (mkTableTy tn) Set.empty (mapFromL _fiName flds) TLHasuraType
+mkRelayTableObj tn descM allowedFields =
+  mkObjTyInfo (Just desc) (mkTableTy tn) Set.empty (mapFromL _fiName fields) TLHasuraType
   where
-    -- TODO: Reuse code from `mkTableObj`
-    flds = nodeIdField:pgColumnFields <> relFlds <> computedFlds
+    fields =
+      let idColumnFilter = \case
+            SFPGColumn columnInfo -> (/=) "id" $ getPGColTxt $ pgiColumn columnInfo
+            _                     -> True
+      in (:) nodeIdField $ mkTableObjectFields True $
+             -- Remove "id" column
+             filter idColumnFilter allowedFields
+
     nodeIdField = mkHsraObjFldInfo Nothing "id" mempty nodeIdType
-    pgColumnFields = map mkPGColFld $
-                     -- Remove "id" column
-                     filter ((/=) "id" . getPGColTxt . pgiColumn) $
-                     getPGColumnFields allowedFlds
-    relFlds = concatMap mkRelationshipField' $ getRelationshipFields allowedFlds
-    computedFlds = map mkComputedFieldFld $ getComputedFields allowedFlds
-    mkRelationshipField' (RelationshipFieldInfo relInfo allowAgg _ _ _ maybePkCols isNullable) =
-      mkRelationshipField allowAgg relInfo True maybePkCols isNullable
-    desc = mkDescriptionWith descM $ "columns and relationships of " <>> tn
+    desc = mkTableObjectDescription tn descM
 
 mkRemoteRelationshipName :: RemoteRelationshipName -> G.Name
 mkRemoteRelationshipName =

From 662264919114130c1545259f6fd35f315dc1e5d0 Mon Sep 17 00:00:00 2001
From: Rishichandra Wawhal <rishi@hasura.io>
Date: Thu, 4 Jun 2020 12:02:38 +0530
Subject: [PATCH 23/29] requested changes

---
 .../src/components/Common/Tooltip/Tooltip.js  | 12 +++--
 .../Services/ApiExplorer/Actions.js           |  6 +--
 .../ApiExplorer/ApiRequest/ApiRequest.js      | 48 +++++++++----------
 .../GraphiQLWrapper/GraphiQLWrapper.js        |  4 +-
 4 files changed, 37 insertions(+), 33 deletions(-)

diff --git a/console/src/components/Common/Tooltip/Tooltip.js b/console/src/components/Common/Tooltip/Tooltip.js
index 75898fb986d0b..2ce7c72454a0b 100644
--- a/console/src/components/Common/Tooltip/Tooltip.js
+++ b/console/src/components/Common/Tooltip/Tooltip.js
@@ -7,12 +7,14 @@ const tooltipGen = message => {
   return <Tooltip id={message}>{message}</Tooltip>;
 };
 
-const ToolTip = ({ message, placement = 'right' }) => (
+const ToolTip = ({ message, placement = 'right', children }) => (
   <OverlayTrigger placement={placement} overlay={tooltipGen(message)}>
-    <i
-      className={`fa fa-question-circle + ${styles.tooltipIcon}`}
-      aria-hidden="true"
-    />
+    {children || (
+      <i
+        className={`fa fa-question-circle + ${styles.tooltipIcon}`}
+        aria-hidden="true"
+      />
+    )}
   </OverlayTrigger>
 );
 
diff --git a/console/src/components/Services/ApiExplorer/Actions.js b/console/src/components/Services/ApiExplorer/Actions.js
index 6d2144860d874..dd22b707a0f33 100644
--- a/console/src/components/Services/ApiExplorer/Actions.js
+++ b/console/src/components/Services/ApiExplorer/Actions.js
@@ -44,9 +44,9 @@ const CREATE_WEBSOCKET_CLIENT = 'ApiExplorer/CREATE_WEBSOCKET_CLIENT';
 const FOCUS_ROLE_HEADER = 'ApiExplorer/FOCUS_ROLE_HEADER';
 const UNFOCUS_ROLE_HEADER = 'ApiExplorer/UNFOCUS_ROLE_HEADER';
 
-const LOADING = 'ApiExplorer/LOADING';
+const SET_LOADING = 'ApiExplorer/SET_LOADING';
 export const setLoading = isLoading => ({
-  type: LOADING,
+  type: SET_LOADING,
   data: isLoading,
 });
 
@@ -638,7 +638,7 @@ const apiExplorerReducer = (state = defaultState, action) => {
         ...state,
         mode: action.mode,
       };
-    case LOADING:
+    case SET_LOADING:
       return {
         ...state,
         loading: action.data,
diff --git a/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js b/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js
index 2b60f9ef33849..06ed33077fa62 100644
--- a/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js
+++ b/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js
@@ -3,10 +3,8 @@ import PropTypes from 'prop-types';
 import jwt from 'jsonwebtoken';
 
 import TextAreaWithCopy from '../../../Common/TextAreaWithCopy/TextAreaWithCopy';
-import OverlayTrigger from 'react-bootstrap/lib/OverlayTrigger';
-import Tooltip from 'react-bootstrap/lib/Tooltip';
 import Modal from '../../../Common/Modal/Modal';
-import TooltipCustom from '../../../Common/Tooltip/Tooltip';
+import Tooltip from '../../../Common/Tooltip/Tooltip';
 
 import {
   changeRequestHeader,
@@ -42,14 +40,6 @@ import { getGraphQLEndpoint } from '../utils';
 import styles from '../ApiExplorer.scss';
 import { ADMIN_SECRET_HEADER_KEY } from '../../../../constants';
 
-const inspectJWTTooltip = (
-  <Tooltip id="tooltip-inspect-jwt">Decode JWT</Tooltip>
-);
-
-const jwtValidityStatus = message => (
-  <Tooltip id="tooltip-jwt-validity-status">{message}</Tooltip>
-);
-
 /* When the page is loaded for the first time, hydrate the header state from the localStorage
  * Keep syncing the localStorage state when user modifies.
  * */
@@ -288,7 +278,7 @@ class ApiRequest extends Component {
                 icons={false}
               />
               <span className={styles.add_mar_right_mid}>Relay API</span>
-              <TooltipCustom
+              <Tooltip
                 id="relay-mode-toggle"
                 placement="left"
                 message={
@@ -445,12 +435,18 @@ class ApiRequest extends Component {
 
             if (isAdminSecret) {
               headerAdminVal = (
-                <i
-                  className={styles.showAdminSecret + ' fa fa-eye'}
-                  data-header-id={i}
-                  aria-hidden="true"
-                  onClick={onShowAdminSecretClicked}
-                />
+                <Tooltip
+                  id="admin-secret-show"
+                  placement="left"
+                  message="Show admin secret"
+                >
+                  <i
+                    className={styles.showAdminSecret + ' fa fa-eye'}
+                    data-header-id={i}
+                    aria-hidden="true"
+                    onClick={onShowAdminSecretClicked}
+                  />
+                </Tooltip>
               );
             }
 
@@ -490,9 +486,13 @@ class ApiRequest extends Component {
 
             if (isAuthHeader && isJWTSet) {
               inspectorIcon = (
-                <OverlayTrigger placement="top" overlay={inspectJWTTooltip}>
+                <Tooltip
+                  id="tooltip-inspect-jwt"
+                  message="Decode JWT"
+                  placement="left"
+                >
                   {getAnalyzeIcon()}
-                </OverlayTrigger>
+                </Tooltip>
               );
             }
 
@@ -635,14 +635,14 @@ class ApiRequest extends Component {
           switch (true) {
             case tokenVerified:
               return (
-                <OverlayTrigger
-                  placement="top"
-                  overlay={jwtValidityStatus('Valid JWT token')}
+                <Tooltip
+                  id="tooltip-jwt-validity-status"
+                  message="Valid JWT token"
                 >
                   <span className={styles.valid_jwt_token}>
                     <i className="fa fa-check" />
                   </span>
-                </OverlayTrigger>
+                </Tooltip>
               );
             case !tokenVerified && JWTError.length > 0:
               return (
diff --git a/console/src/components/Services/ApiExplorer/GraphiQLWrapper/GraphiQLWrapper.js b/console/src/components/Services/ApiExplorer/GraphiQLWrapper/GraphiQLWrapper.js
index 51f91961ecae4..c383baa1db78b 100644
--- a/console/src/components/Services/ApiExplorer/GraphiQLWrapper/GraphiQLWrapper.js
+++ b/console/src/components/Services/ApiExplorer/GraphiQLWrapper/GraphiQLWrapper.js
@@ -251,4 +251,6 @@ const mapStateToProps = state => ({
   loading: state.apiexplorer.loading,
 });
 
-export default connect(mapStateToProps)(GraphiQLWrapper);
+const GraphiQLWrapperConnected = connect(mapStateToProps)(GraphiQLWrapper);
+
+export default GraphiQLWrapperConnected;

From 2d836ea22c4173695b051e39cece9c8533d2c81f Mon Sep 17 00:00:00 2001
From: Rishichandra Wawhal <rishi@hasura.io>
Date: Thu, 4 Jun 2020 12:12:15 +0530
Subject: [PATCH 24/29] persist graphiql mode

---
 console/src/components/Services/ApiExplorer/Actions.js   | 1 +
 .../Services/ApiExplorer/ApiRequest/ApiRequest.js        | 5 ++++-
 .../components/Services/ApiExplorer/ApiRequest/utils.js  | 8 ++++++++
 console/src/components/Services/ApiExplorer/state.js     | 9 ++++++---
 4 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/console/src/components/Services/ApiExplorer/Actions.js b/console/src/components/Services/ApiExplorer/Actions.js
index dd22b707a0f33..11aca6923995d 100644
--- a/console/src/components/Services/ApiExplorer/Actions.js
+++ b/console/src/components/Services/ApiExplorer/Actions.js
@@ -634,6 +634,7 @@ const apiExplorerReducer = (state = defaultState, action) => {
         },
       };
     case SWITCH_GRAPHIQL_MODE:
+
       return {
         ...state,
         mode: action.mode,
diff --git a/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js b/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js
index 06ed33077fa62..8b94fc74733b1 100644
--- a/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js
+++ b/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js
@@ -34,6 +34,7 @@ import {
   getPersistedAdminSecretHeaderWasAdded,
   persistAdminSecretHeaderWasAdded,
   removePersistedAdminSecretHeaderWasAdded,
+  persistGraphiQLMode,
 } from './utils';
 import { getGraphQLEndpoint } from '../utils';
 
@@ -223,7 +224,9 @@ class ApiRequest extends Component {
 
       const toggleGraphiqlMode = () => {
         if (loading) return;
-        dispatch(switchGraphiQLMode(mode === 'relay' ? 'graphql' : 'relay'));
+        const newMode = (mode === 'relay' ? 'graphql' : 'relay');
+        persistGraphiQLMode(newMode);
+        dispatch(switchGraphiQLMode(newMode));
       };
 
       return (
diff --git a/console/src/components/Services/ApiExplorer/ApiRequest/utils.js b/console/src/components/Services/ApiExplorer/ApiRequest/utils.js
index 6c6a2f92f1386..bb3bba96f6baf 100644
--- a/console/src/components/Services/ApiExplorer/ApiRequest/utils.js
+++ b/console/src/components/Services/ApiExplorer/ApiRequest/utils.js
@@ -147,3 +147,11 @@ export const parseAuthHeader = header => {
 
   return { isAuthHeader, token };
 };
+
+export const persistGraphiQLMode = (mode) => {
+  window.localStorage.setItem('ApiExplorer:GraphiQLMode', mode);
+};
+
+export const getPersistedGraphiQLMode = () => {
+  return window.localStorage.getItem('ApiExplorer:GraphiQLMode');
+};
diff --git a/console/src/components/Services/ApiExplorer/state.js b/console/src/components/Services/ApiExplorer/state.js
index 69ad1e9a35a43..f60f81816d4c9 100644
--- a/console/src/components/Services/ApiExplorer/state.js
+++ b/console/src/components/Services/ApiExplorer/state.js
@@ -1,4 +1,7 @@
-import endpoints from '../../../Endpoints';
+import { getPersistedGraphiQLMode } from './ApiRequest/utils'
+import { getGraphQLEndpoint } from './utils'
+
+const persistedGraphiqlMode = getPersistedGraphiQLMode();
 
 const defaultHeader = [
   {
@@ -27,7 +30,7 @@ const dataApisContent = [
     },
     request: {
       method: 'POST',
-      url: endpoints.graphQLUrl,
+      url: getGraphQLEndpoint(persistedGraphiqlMode),
       headers: defaultHeader,
       headersInitialised: false,
       bodyType: 'graphql',
@@ -60,7 +63,7 @@ const defaultState = {
   explorerData,
   authApiExpanded: 'Username-password Login',
   headerFocus: false,
-  mode: 'graphql',
+  mode: persistedGraphiqlMode,
   loading: false,
 };
 

From 2c0725d1da3614791a843b100348d36374bbffed Mon Sep 17 00:00:00 2001
From: Rishichandra Wawhal <rishi@hasura.io>
Date: Thu, 4 Jun 2020 20:03:34 +0530
Subject: [PATCH 25/29] lint

---
 console/src/components/Services/ApiExplorer/Actions.js        | 1 -
 .../components/Services/ApiExplorer/ApiRequest/ApiRequest.js  | 2 +-
 .../src/components/Services/ApiExplorer/ApiRequest/utils.js   | 2 +-
 console/src/components/Services/ApiExplorer/state.js          | 4 ++--
 4 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/console/src/components/Services/ApiExplorer/Actions.js b/console/src/components/Services/ApiExplorer/Actions.js
index 11aca6923995d..dd22b707a0f33 100644
--- a/console/src/components/Services/ApiExplorer/Actions.js
+++ b/console/src/components/Services/ApiExplorer/Actions.js
@@ -634,7 +634,6 @@ const apiExplorerReducer = (state = defaultState, action) => {
         },
       };
     case SWITCH_GRAPHIQL_MODE:
-
       return {
         ...state,
         mode: action.mode,
diff --git a/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js b/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js
index 8b94fc74733b1..b860d5f868e0d 100644
--- a/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js
+++ b/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js
@@ -224,7 +224,7 @@ class ApiRequest extends Component {
 
       const toggleGraphiqlMode = () => {
         if (loading) return;
-        const newMode = (mode === 'relay' ? 'graphql' : 'relay');
+        const newMode = mode === 'relay' ? 'graphql' : 'relay';
         persistGraphiQLMode(newMode);
         dispatch(switchGraphiQLMode(newMode));
       };
diff --git a/console/src/components/Services/ApiExplorer/ApiRequest/utils.js b/console/src/components/Services/ApiExplorer/ApiRequest/utils.js
index bb3bba96f6baf..837aedcac75b2 100644
--- a/console/src/components/Services/ApiExplorer/ApiRequest/utils.js
+++ b/console/src/components/Services/ApiExplorer/ApiRequest/utils.js
@@ -148,7 +148,7 @@ export const parseAuthHeader = header => {
   return { isAuthHeader, token };
 };
 
-export const persistGraphiQLMode = (mode) => {
+export const persistGraphiQLMode = mode => {
   window.localStorage.setItem('ApiExplorer:GraphiQLMode', mode);
 };
 
diff --git a/console/src/components/Services/ApiExplorer/state.js b/console/src/components/Services/ApiExplorer/state.js
index f60f81816d4c9..ae426e458ca91 100644
--- a/console/src/components/Services/ApiExplorer/state.js
+++ b/console/src/components/Services/ApiExplorer/state.js
@@ -1,5 +1,5 @@
-import { getPersistedGraphiQLMode } from './ApiRequest/utils'
-import { getGraphQLEndpoint } from './utils'
+import { getPersistedGraphiQLMode } from './ApiRequest/utils';
+import { getGraphQLEndpoint } from './utils';
 
 const persistedGraphiqlMode = getPersistedGraphiQLMode();
 

From 6cf3c97f23913eda14162485404692c114423c0e Mon Sep 17 00:00:00 2001
From: Rishichandra Wawhal <rishi@hasura.io>
Date: Mon, 8 Jun 2020 15:59:37 +0530
Subject: [PATCH 26/29] reduce margin betweent toggle and URL; remove usage of
 negative margin

---
 console/src/components/Common/Common.scss                   | 6 ------
 .../src/components/Services/ApiExplorer/ApiExplorer.scss    | 1 -
 .../Services/ApiExplorer/ApiRequest/ApiRequest.js           | 5 +++--
 3 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/console/src/components/Common/Common.scss b/console/src/components/Common/Common.scss
index 43ff8bde87fb4..c4866dfdce6e7 100644
--- a/console/src/components/Common/Common.scss
+++ b/console/src/components/Common/Common.scss
@@ -1259,12 +1259,6 @@ code {
   display: block;
   top: 0;
   z-index: 11;
-
-  .stickySeparator {
-    padding-top: 60px;
-    margin-left: -15px;
-    margin-right: -15px;
-  }
 }
 
 .fixed_header_internal_link {
diff --git a/console/src/components/Services/ApiExplorer/ApiExplorer.scss b/console/src/components/Services/ApiExplorer/ApiExplorer.scss
index 6e4f6154549ae..204356d1bdb7a 100644
--- a/console/src/components/Services/ApiExplorer/ApiExplorer.scss
+++ b/console/src/components/Services/ApiExplorer/ApiExplorer.scss
@@ -829,6 +829,5 @@ label {
 }
 
 .graphiqlModeToggle {
-  margin-top: -5px;
   float: right;
 }
diff --git a/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js b/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js
index b860d5f868e0d..cfe1ca0284fe9 100644
--- a/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js
+++ b/console/src/components/Services/ApiExplorer/ApiRequest/ApiRequest.js
@@ -246,7 +246,9 @@ class ApiRequest extends Component {
               styles.stickyHeader
             }
           >
-            <div className={'col-xs-12 ' + styles.padd_remove}>
+            <div
+              className={`col-xs-12 ${styles.padd_remove} ${styles.add_mar_bottom_mid}`}
+            >
               <div
                 className={
                   'input-group ' +
@@ -268,7 +270,6 @@ class ApiRequest extends Component {
                 />
               </div>
             </div>
-            <div className={styles.stickySeparator} />
             <div
               className={`${styles.display_flex} ${styles.graphiqlModeToggle} ${styles.cursorPointer}`}
               onClick={toggleGraphiqlMode}

From 5a17d5151b6ac8814781c86d887b57fe36f624d8 Mon Sep 17 00:00:00 2001
From: rakeshkky <12475069+rakeshkky@users.noreply.github.com>
Date: Mon, 8 Jun 2020 16:00:07 +0530
Subject: [PATCH 27/29] revert the logic of remote schema query execution

-> Do not validate the remote schema query. The remote server take care
of it.
---
 server/src-lib/Hasura/GraphQL/Execute.hs             | 7 +++----
 server/src-lib/Hasura/GraphQL/Transport/HTTP.hs      | 9 +--------
 server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs | 2 +-
 server/tests-py/test_schema_stitching.py             | 4 ++--
 4 files changed, 7 insertions(+), 15 deletions(-)

diff --git a/server/src-lib/Hasura/GraphQL/Execute.hs b/server/src-lib/Hasura/GraphQL/Execute.hs
index 712d4b3ab92b8..568ae3569e20c 100644
--- a/server/src-lib/Hasura/GraphQL/Execute.hs
+++ b/server/src-lib/Hasura/GraphQL/Execute.hs
@@ -64,7 +64,7 @@ import qualified Hasura.Server.Telemetry.Counters       as Telem
 -- intermediate passes
 data GQExecPlan a
   = GExPHasura !a
-  | GExPRemote !RemoteSchemaInfo !G.TypedOperationDefinition !VQ.RootSelectionSet
+  | GExPRemote !RemoteSchemaInfo !G.TypedOperationDefinition
   deriving (Functor, Foldable, Traversable)
 
 -- | Execution context
@@ -148,9 +148,8 @@ getExecPlanPartial userInfo sc queryType enableAL req = do
     VT.TLHasuraType -> do
       rootSelSet <- runReaderT (VQ.validateGQ queryParts) gCtx
       pure $ GExPHasura (gCtx, rootSelSet)
-    VT.TLRemoteType _ rsi -> do
-      rootSelSet <- runReaderT (VQ.validateGQ queryParts) gCtx
-      pure $ GExPRemote rsi opDef rootSelSet
+    VT.TLRemoteType _ rsi ->
+      pure $ GExPRemote rsi opDef
     VT.TLCustom ->
       throw500 "unexpected custom type for top level field"
   where
diff --git a/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs b/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs
index bb1aee4320c22..8676081962b02 100644
--- a/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs
+++ b/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs
@@ -47,16 +47,9 @@ runGQ reqId userInfo reqHdrs queryType req = do
       E.GExPHasura resolvedOp -> do
         (telemTimeIO, telemQueryType, respHdrs, resp) <- runHasuraGQ reqId req userInfo resolvedOp
         return (telemCacheHit, Telem.Local, (telemTimeIO, telemQueryType, HttpResponse resp respHdrs))
-      E.GExPRemote rsi opDef _ -> do
+      E.GExPRemote rsi opDef  -> do
         let telemQueryType | G._todType opDef == G.OperationTypeMutation = Telem.Mutation
                            | otherwise = Telem.Query
-            -- rewrittenQuery =
-            --   GQLReq { _grQuery = GQLQueryText $ GP.renderExecutableDoc $
-            --                       G.ExecutableDocument $ pure $
-            --                       toGraphQLOperation rootSelSet
-            --          , _grVariables = Nothing
-            --          , _grOperationName = Nothing
-            --          }
         (telemTimeIO, resp) <- E.execRemoteGQ reqId userInfo reqHdrs req rsi $ G._todType opDef
         return (telemCacheHit, Telem.Remote, (telemTimeIO, telemQueryType, resp))
   let telemTimeIO = convertDuration telemTimeIO_DT
diff --git a/server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs b/server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs
index c35d7706c7d79..31c36007c2455 100644
--- a/server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs
+++ b/server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs
@@ -318,7 +318,7 @@ onStart serverEnv wsConn (StartMsg opId q) = catchAndIgnore $ do
   case execPlan of
     E.GExPHasura resolvedOp ->
       runHasuraGQ timerTot telemCacheHit requestId q userInfo resolvedOp
-    E.GExPRemote rsi opDef _  ->
+    E.GExPRemote rsi opDef  ->
       runRemoteGQ timerTot telemCacheHit execCtx requestId userInfo reqHdrs opDef rsi
   where
     telemTransport = Telem.HTTP
diff --git a/server/tests-py/test_schema_stitching.py b/server/tests-py/test_schema_stitching.py
index 7bd7985cc7c1c..642d3148e995f 100644
--- a/server/tests-py/test_schema_stitching.py
+++ b/server/tests-py/test_schema_stitching.py
@@ -364,10 +364,10 @@ def test_remote_query_error(self, ws_client):
         try:
             ev = next(resp)
             print(ev)
-            assert ev['type'] == 'error' and ev['id'] == query_id, ev
+            assert ev['type'] == 'data' and ev['id'] == query_id, ev
             assert 'errors' in ev['payload']
             assert ev['payload']['errors'][0]['message'] == \
-                'field "blah" not found in type: \'User\''
+                'Cannot query field "blah" on type "User".'
         finally:
             ws_client.stop(query_id)
 

From 950815696cc94c531837f400dbd5ee3203f73392 Mon Sep 17 00:00:00 2001
From: rakeshkky <12475069+rakeshkky@users.noreply.github.com>
Date: Mon, 8 Jun 2020 16:03:41 +0530
Subject: [PATCH 28/29] filter 'id' column by taking custom field name into
 account

---
 server/src-lib/Hasura/GraphQL/Schema/Select.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/server/src-lib/Hasura/GraphQL/Schema/Select.hs b/server/src-lib/Hasura/GraphQL/Schema/Select.hs
index afb6c60fe2840..f5738ff365576 100644
--- a/server/src-lib/Hasura/GraphQL/Schema/Select.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/Select.hs
@@ -241,7 +241,7 @@ mkRelayTableObj tn descM allowedFields =
   where
     fields =
       let idColumnFilter = \case
-            SFPGColumn columnInfo -> (/=) "id" $ getPGColTxt $ pgiColumn columnInfo
+            SFPGColumn columnInfo -> (/=) "id" $ pgiName columnInfo
             _                     -> True
       in (:) nodeIdField $ mkTableObjectFields True $
              -- Remove "id" column

From acca92c7c1ef1b1dbf975042395484adbb119de3 Mon Sep 17 00:00:00 2001
From: Vamshi Surabhi <0x777@users.noreply.github.com>
Date: Mon, 8 Jun 2020 17:36:13 +0530
Subject: [PATCH 29/29] Update cabal.project

---
 server/cabal.project | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/server/cabal.project b/server/cabal.project
index 001964cfc2a05..abb20a5adedbc 100644
--- a/server/cabal.project
+++ b/server/cabal.project
@@ -40,8 +40,8 @@ source-repository-package
 
 source-repository-package
   type: git
-  location: https://github.com/0x777/graphql-parser-hs.git
-  tag: 09ea73cecb3b8d433274cade8ad6954c150c2dea
+  location: https://github.com/hasura/graphql-parser-hs.git
+  tag: f4a093981ca5626982a17c2bfaad047cc0834a81
 
 source-repository-package
   type: git