org.apache.spark.sql.execution.joins.ShuffledHashJoinExec.scala Maven / Gradle / Ivy
/*
* 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.execution.joins
import org.apache.spark.TaskContext
import org.apache.spark.rdd.RDD
import org.apache.spark.sql.catalyst.InternalRow
import org.apache.spark.sql.catalyst.expressions.Expression
import org.apache.spark.sql.catalyst.plans._
import org.apache.spark.sql.catalyst.plans.physical._
import org.apache.spark.sql.execution.{BinaryExecNode, SparkPlan}
import org.apache.spark.sql.execution.metric.SQLMetrics
/**
* Performs a hash join of two child relations by first shuffling the data using the join keys.
*/
case class ShuffledHashJoinExec(
leftKeys: Seq[Expression],
rightKeys: Seq[Expression],
joinType: JoinType,
buildSide: BuildSide,
condition: Option[Expression],
left: SparkPlan,
right: SparkPlan)
extends BinaryExecNode with HashJoin {
override lazy val metrics = Map(
"numOutputRows" -> SQLMetrics.createMetric(sparkContext, "number of output rows"),
"buildDataSize" -> SQLMetrics.createSizeMetric(sparkContext, "data size of build side"),
"buildTime" -> SQLMetrics.createTimingMetric(sparkContext, "time to build hash map"),
"avgHashProbe" -> SQLMetrics.createAverageMetric(sparkContext, "avg hash probe"))
override def requiredChildDistribution: Seq[Distribution] =
HashClusteredDistribution(leftKeys) :: HashClusteredDistribution(rightKeys) :: Nil
private def buildHashedRelation(iter: Iterator[InternalRow]): HashedRelation = {
val buildDataSize = longMetric("buildDataSize")
val buildTime = longMetric("buildTime")
val start = System.nanoTime()
val context = TaskContext.get()
val relation = HashedRelation(iter, buildKeys, taskMemoryManager = context.taskMemoryManager())
buildTime += (System.nanoTime() - start) / 1000000
buildDataSize += relation.estimatedSize
// This relation is usually used until the end of task.
context.addTaskCompletionListener(_ => relation.close())
relation
}
protected override def doExecute(): RDD[InternalRow] = {
val numOutputRows = longMetric("numOutputRows")
val avgHashProbe = longMetric("avgHashProbe")
streamedPlan.execute().zipPartitions(buildPlan.execute()) { (streamIter, buildIter) =>
val hashed = buildHashedRelation(buildIter)
join(streamIter, hashed, numOutputRows, avgHashProbe)
}
}
}