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https://issues.apache.org/jira/browse/SPARK-51272?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Asif updated SPARK-51272:
-------------------------
Labels: spark-core (was: )
> Race condition in DagScheduler can result in failure of retrying all
> partitions for non deterministic partitioning key
> ----------------------------------------------------------------------------------------------------------------------
>
> Key: SPARK-51272
> URL: https://issues.apache.org/jira/browse/SPARK-51272
> Project: Spark
> Issue Type: Bug
> Components: Spark Core
> Affects Versions: 3.5.4
> Reporter: Asif
> Priority: Major
> Labels: spark-core
> Fix For: 4.0.0
>
> Attachments: BugTest.txt, bugrepro.patch
>
>
> In DagScheduler, where a successful task completion occurs concurrently with
> a task failure , for an inDeterminate stage, results in a situation , where
> instead of re-executing all partitions, only some are retried. This results
> in data loss.
> The race condition identified is as follows:
> a) A successful result stage task, is yet to mark in the boolean array
> tracking partitions success/failure as true/false.
> b) A concurrent failed result task, belonging to an InDeterminate stage,
> idenitfies all the stages which needs/ can be rolled back. For Result Stage,
> it looks into the array of successful partitions. As none is marked as true,
> the ResultStage and dependent stages are delegated to thread pool for retry.
> c) Between the time of collecting stages to rollback and re-try of stages,
> the successful task marks boolean as true.
> d) The Retry of Stage, as a result, misses the partition marked as
> successful, for retry.
>
> Attaching two files for reproducing the functional bug , showing the race
> condition causing data corruption.
> I am attaching 2 files for bug test
> # bugrepro.patch
> This is needed to coax the single VM test to reproduce the issue. It has lots
> of interception and tweaks to ensure that system is able to hit the data loss
> situation.
> ( like each partition writes only a shuffle file containing keys evaluating
> to same hashCode and deleting the shuffle file at right time etc)
> # The BugTest itself.
> a) If the bugrepro.patch is applied to current master and the BugTest run, it
> will fail immediately with assertion failure where instead of 12 rows, 6 rows
> show up in result.
> b) If the bugrepro.patch is applied on top of PR
> [https://github.com/apache/spark/pull/50029|https://github.com/apache/spark/pull/50029]
> , then the BugTest will fail after one or two or more iterations,
> indicating the race condition in DataScheduler/Stage interaction.
> c) But if the same BugTest is run on branch containing fix for this bug as
> well as the PR
> [https://github.com/apache/spark/pull/50029|https://github.com/apache/spark/pull/50029],
> it will pass in all the 100 iteration.
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