maryannxue commented on a change in pull request #27893: [SPARK-31134][SQL]
optimize skew join after shuffle partitions are coalesced
URL: https://github.com/apache/spark/pull/27893#discussion_r392280534
##########
File path:
sql/core/src/main/scala/org/apache/spark/sql/execution/adaptive/OptimizeSkewedJoin.scala
##########
@@ -328,6 +287,48 @@ case class OptimizeSkewedJoin(conf: SQLConf) extends
Rule[SparkPlan] {
}
}
+private object ShuffleStage {
+ def unapply(plan: SparkPlan): Option[ShuffleStageInfo] = plan match {
+ case s: ShuffleQueryStageExec =>
+ val mapStats = getMapStats(s)
+ val sizes = mapStats.bytesByPartitionId
+ val partitions = sizes.zipWithIndex.map {
+ case (size, i) => CoalescedPartitionSpec(i, i + 1) -> size
+ }
+ Some(ShuffleStageInfo(s, mapStats, partitions))
+
+ case CustomShuffleReaderExec(s: ShuffleQueryStageExec, partitionSpecs, _)
=>
+ val mapStats = getMapStats(s)
+ val sizes = mapStats.bytesByPartitionId
+ val partitions = partitionSpecs.map {
+ case spec @ CoalescedPartitionSpec(start, end) =>
+ var sum = 0L
+ var i = start
+ while (i < end) {
+ sum += sizes(i)
+ i += 1
+ }
+ spec -> sum
+ case other => throw new IllegalArgumentException(
+ s"Expect CoalescedPartitionSpec but got $other")
+ }
+ Some(ShuffleStageInfo(s, mapStats, partitions))
+
+ case _ => None
+ }
+
+ private def getMapStats(stage: ShuffleQueryStageExec): MapOutputStatistics =
{
+ assert(stage.resultOption.isDefined, "ShuffleQueryStageExec should" +
+ " already be ready when executing OptimizeSkewedPartitions rule")
+ stage.resultOption.get.asInstanceOf[MapOutputStatistics]
+ }
+}
+
+private case class ShuffleStageInfo(
Review comment:
nit: partitions -> partitionsWithSizes?
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