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https://issues.apache.org/jira/browse/FLINK-12131?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16815110#comment-16815110
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Zhu Zhu commented on FLINK-12131:
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Hi [~till.rohrmann], I think this fix is needed to make region
failover(FLINK-4256) work.
I posted a detailed design above. Could you take a look at it?
I can start a PR if you think it is fine.
> Resetting ExecutionVertex in region failover may cause inconsistency of
> IntermediateResult status
> -------------------------------------------------------------------------------------------------
>
> Key: FLINK-12131
> URL: https://issues.apache.org/jira/browse/FLINK-12131
> Project: Flink
> Issue Type: Bug
> Components: Runtime / Coordination
> Affects Versions: 1.9.0
> Reporter: Zhu Zhu
> Assignee: Zhu Zhu
> Priority: Major
>
> Two status may not be correct with region failover and current reset logic.
> # *numberOfRunningProducers* in *IntermediateResult*.
> # *hasDataProduced* in *IntermediateResultPartition*.
> This is because currently only when the *ExecutionJobVertex* is reset will
> the related *IntermediateResult*(and the inner *IntermediateResultPartition*)
> get reset. But region failover resets the affected *ExecutionVertex(ex)*,
> rather than the entire *ExecutionJobVertex*.
> Problems below may occur as a result:
> # when a FINISHED vertex is restarted and finishes again, the
> *IntermediateResult.numberOfRunningProducers* may drop below 0 and throws
> exception to trigger global failover
> # the *IntermediateResult.numberOfRunningProducers* can be smaller than
> fact, letting the downstream vertices scheduled earlier than expected
> # the *IntermediateResultPartition* is reset and not started yet but the
> *hasDataProduced* remains true
> That's why I'd propose we add IntermediateResult status adjust logic to
> *ExecutionVertex.**resetForNewExecution()***.
> Detailed design:
> [https://docs.google.com/document/d/1YA3k8rwDEv1UdaV9NwoDmwc-XorG__JUXlpyJtDs4Ss/edit?usp=sharing]
>
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