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https://issues.apache.org/jira/browse/FLINK-14214?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16938663#comment-16938663
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Piotr Nowojski commented on FLINK-14214:
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After the performance improvement of
https://issues.apache.org/jira/browse/FLINK-11859, which is unrelated to this
performance regression, I'm struggling to reproduce this issue. I would be
afraid that trying to reproduce it, would require substantial effort, that
might be even not very visible to the final user.
Additionally when serialisation optimisation
(https://issues.apache.org/jira/browse/FLINK-11859) is accounted for, it looks
like even with this performance regression, we have better throughput compared
to 1.9.
Because of that, I would suggest to close the ticket, unless someone is willing
to spend more time investigating it.
> Performance regression in TwoInputStreamOperator
> ------------------------------------------------
>
> Key: FLINK-14214
> URL: https://issues.apache.org/jira/browse/FLINK-14214
> Project: Flink
> Issue Type: Bug
> Components: Runtime / Task
> Affects Versions: 1.10.0
> Reporter: Piotr Nowojski
> Assignee: Piotr Nowojski
> Priority: Major
> Labels: pull-request-available
> Time Spent: 10m
> Remaining Estimate: 0h
>
> https://issues.apache.org/jira/browse/FLINK-13051 introduced a performance
> regression visible for example
> [here|http://codespeed.dak8s.net:8000/timeline/#/?exe=1,3&ben=twoInputMapSink&env=2&revs=200&equid=off&quarts=off&extr=off]
> as a drop on August 30th (note that the later performance improvement is
> caused by serialisation improvement, which is unrelated to the previous slow
> down).
> Probable suspect is the following {{.isDone()}} check executed inside
> {{StreamTwoInputProcessor}} once per record:
> {code:java}
> // to avoid starvation, if the input selection is ALL and availableInputsMask
> is not ALL,
> // always try to check and set the availability of another input
> // TODO: because this can be a costly operation (checking volatile inside
> CompletableFuture`
> // this might be optimized to only check once per processed NetworkBuffer
> if (inputSelectionHandler.shouldSetAvailableForAnotherInput()) {
> checkAndSetAvailable(1 - readingInputIndex);
> }
> {code}
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