/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.spark.sql

import org.apache.spark.sql.catalyst.InternalRow
import org.apache.spark.sql.catalyst.encoders.RowEncoder
import org.apache.spark.sql.catalyst.expressions.UnsafeProjection
import org.apache.spark.sql.types._
import org.apache.spark.util.Benchmark

/**
 * Benchmark `UnsafeProjection` for fixed-length/primitive-type fields.
 */
object UnsafeProjectionBenchmark {

  def generateRows(schema: StructType, numRows: Int): Array[InternalRow] = {
    val generator = RandomDataGenerator.forType(schema, nullable = false).get
    val encoder = RowEncoder(schema)
    (1 to numRows).map(_ => encoder.toRow(generator().asInstanceOf[Row]).copy()).toArray
  }

  def main(args: Array[String]) {
    val iters = 1024 * 16
    val numRows = 1024 * 16

    val benchmark = new Benchmark("unsafe projection", iters * numRows)


    val schema1 = new StructType().add("l", LongType, false)
    val attrs1 = schema1.toAttributes
    val rows1 = generateRows(schema1, numRows)
    val projection1 = UnsafeProjection.create(attrs1, attrs1)

    benchmark.addCase("single long") { _ =>
      for (_ <- 1 to iters) {
        var sum = 0L
        var i = 0
        while (i < numRows) {
          sum += projection1(rows1(i)).getLong(0)
          i += 1
        }
      }
    }

    val schema2 = new StructType().add("l", LongType, true)
    val attrs2 = schema2.toAttributes
    val rows2 = generateRows(schema2, numRows)
    val projection2 = UnsafeProjection.create(attrs2, attrs2)

    benchmark.addCase("single nullable long") { _ =>
      for (_ <- 1 to iters) {
        var sum = 0L
        var i = 0
        while (i < numRows) {
          sum += projection2(rows2(i)).getLong(0)
          i += 1
        }
      }
    }


    val schema3 = new StructType()
      .add("boolean", BooleanType, false)
      .add("byte", ByteType, false)
      .add("short", ShortType, false)
      .add("int", IntegerType, false)
      .add("long", LongType, false)
      .add("float", FloatType, false)
      .add("double", DoubleType, false)
    val attrs3 = schema3.toAttributes
    val rows3 = generateRows(schema3, numRows)
    val projection3 = UnsafeProjection.create(attrs3, attrs3)

    benchmark.addCase("7 primitive types") { _ =>
      for (_ <- 1 to iters) {
        var sum = 0L
        var i = 0
        while (i < numRows) {
          sum += projection3(rows3(i)).getLong(0)
          i += 1
        }
      }
    }


    val schema4 = new StructType()
      .add("boolean", BooleanType, true)
      .add("byte", ByteType, true)
      .add("short", ShortType, true)
      .add("int", IntegerType, true)
      .add("long", LongType, true)
      .add("float", FloatType, true)
      .add("double", DoubleType, true)
    val attrs4 = schema4.toAttributes
    val rows4 = generateRows(schema4, numRows)
    val projection4 = UnsafeProjection.create(attrs4, attrs4)

    benchmark.addCase("7 nullable primitive types") { _ =>
      for (_ <- 1 to iters) {
        var sum = 0L
        var i = 0
        while (i < numRows) {
          sum += projection4(rows4(i)).getLong(0)
          i += 1
        }
      }
    }


    /*
    Intel(R) Core(TM) i7-4960HQ CPU @ 2.60GHz
    unsafe projection:                 Avg Time(ms)    Avg Rate(M/s)  Relative Rate
    -------------------------------------------------------------------------------
    single long                             1533.34           175.07         1.00 X
    single nullable long                    2306.73           116.37         0.66 X
    primitive types                         8403.93            31.94         0.18 X
    nullable primitive types               12448.39            21.56         0.12 X
     */
    benchmark.run()
  }
}
