spark ShuffledJoin 源码
spark ShuffledJoin 代码
文件路径:/sql/core/src/main/scala/org/apache/spark/sql/execution/joins/ShuffledJoin.scala
/*
* 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.sql.catalyst.expressions.Attribute
import org.apache.spark.sql.catalyst.plans.{ExistenceJoin, FullOuter, InnerLike, LeftExistence, LeftOuter, RightOuter}
import org.apache.spark.sql.catalyst.plans.physical.{ClusteredDistribution, Distribution, Partitioning, PartitioningCollection, UnknownPartitioning, UnspecifiedDistribution}
/**
* Holds common logic for join operators by shuffling two child relations
* using the join keys.
*/
trait ShuffledJoin extends JoinCodegenSupport {
def isSkewJoin: Boolean
override def nodeName: String = {
if (isSkewJoin) super.nodeName + "(skew=true)" else super.nodeName
}
override def stringArgs: Iterator[Any] = super.stringArgs.toSeq.dropRight(1).iterator
override def requiredChildDistribution: Seq[Distribution] = {
if (isSkewJoin) {
// We re-arrange the shuffle partitions to deal with skew join, and the new children
// partitioning doesn't satisfy `HashClusteredDistribution`.
UnspecifiedDistribution :: UnspecifiedDistribution :: Nil
} else {
ClusteredDistribution(leftKeys) :: ClusteredDistribution(rightKeys) :: Nil
}
}
override def outputPartitioning: Partitioning = joinType match {
case _: InnerLike =>
PartitioningCollection(Seq(left.outputPartitioning, right.outputPartitioning))
case LeftOuter => left.outputPartitioning
case RightOuter => right.outputPartitioning
case FullOuter => UnknownPartitioning(left.outputPartitioning.numPartitions)
case LeftExistence(_) => left.outputPartitioning
case x =>
throw new IllegalArgumentException(
s"ShuffledJoin should not take $x as the JoinType")
}
override def output: Seq[Attribute] = {
joinType match {
case _: InnerLike =>
left.output ++ right.output
case LeftOuter =>
left.output ++ right.output.map(_.withNullability(true))
case RightOuter =>
left.output.map(_.withNullability(true)) ++ right.output
case FullOuter =>
(left.output ++ right.output).map(_.withNullability(true))
case j: ExistenceJoin =>
left.output :+ j.exists
case LeftExistence(_) =>
left.output
case x =>
throw new IllegalArgumentException(
s"${getClass.getSimpleName} not take $x as the JoinType")
}
}
}
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