Details
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Bug
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Status: Resolved
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Minor
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Resolution: Fixed
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2.1.0
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None
Description
ShuffleId is determined before job submitted. But it's hard to predict stageId by shuffleId.
Stage is created in DAGScheduler(
https://github.com/apache/spark/blob/master/core/src/main/scala/org/apache/spark/scheduler/DAGScheduler.scala#L381), but the order is n
ot determined.
I added a log(println(s"Creating ShufflMapStage-$id on shuffle-${shuffleDep.shuffleId}")) after (https://github.com/apache/spark/blob/master/core/src/main/scala/org/apache/spark/scheduler/DAGScheduler.scala#L331), when testing BasicSchedulerIntegrationSuite:"multi-stage job". It will print:
Creating ShufflMapStage-0 on shuffle-0
Creating ShufflMapStage-1 on shuffle-2
Creating ShufflMapStage-2 on shuffle-1
Creating ShufflMapStage-3 on shuffle-3
or
Creating ShufflMapStage-0 on shuffle-1
Creating ShufflMapStage-1 on shuffle-3
Creating ShufflMapStage-2 on shuffle-0
Creating ShufflMapStage-3 on shuffle-2
So It might be better to avoid generating the MapStatus by stageId.
