[jira] [Updated] (FLINK-39902) RescaleTimelineITCase.testRescaleTerminatedByJobFinished fails due to race between task unblock and recorded rescale

["ASF GitHub Bot (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/FLINK-39902?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

ASF GitHub Bot updated FLINK-39902:
-----------------------------------
    Labels: pull-request-available test-stability  (was: test-stability)

> RescaleTimelineITCase.testRescaleTerminatedByJobFinished fails due to race between task unblock and recorded rescale
> --------------------------------------------------------------------------------------------------------------------
>
>                 Key: FLINK-39902
>                 URL: https://issues.apache.org/jira/browse/FLINK-39902
>             Project: Flink
>          Issue Type: Bug
>          Components: Runtime / Coordination
>            Reporter: Martijn Visser
>            Assignee: Martijn Visser
>            Priority: Major
>              Labels: pull-request-available, test-stability
>
> testRescaleTerminatedByJobFinished is flaky on slow/loaded CI and has failed on
> both the default and adaptive scheduler legs of the master mirror:
> - 20260609.1 (buildId 75795), test_cron_adaptive_scheduler core https://dev.azure.com/apache-flink/98463496-1af2-4620-8eab-a2ecc1a2e6fe/_build/results?buildId=75795
> - 20260604.4 (buildId 75621), test_ci core https://dev.azure.com/apache-flink/98463496-1af2-4620-8eab-a2ecc1a2e6fe/_build/results?buildId=75621
> Failure:
> {noformat}
>   RescaleTimelineITCase.testRescaleTerminatedByJobFinished:284
>       ->waitUntilConditionWithTimeout:660 » Timeout
> {noformat}
> Root cause:
> The test submits a blocking job at parallelism 4 (full cluster capacity) and
> requests an upscale to parallelism 8. Because 8 exceeds the available slots, the
> rescale never changes the running parallelism and is only observable as a second
> entry in the recorded rescale history (added by DefaultRescaleTimeline when the
> rescale starts). The test calls OnceBlockingNoOpInvokable.unblock() immediately
> after the requirement update, racing the scheduler's reaction to that update. On
> a slow machine the no-op task finishes before the second rescale is started and
> recorded, so the history stays at size 1 and the size-2 / JOB_FINISHED condition
> times out after 10s. Sibling tests avoid this by waiting for the new parallelism
> via waitForVertexParallelismReachedAndJobRunning before unblocking, but that
> helper cannot be used here since parallelism 8 is unreachable.
> Proposed fix (test-only, assertion-preserving):
> Wait until the second rescale has been recorded (history size == 2) before
> unblocking the task, so the in-progress rescale resolves to JOB_FINISHED once the
> job finishes. Move the assumeThat(enabledRescaleHistory(...)) ahead of the
> requirement update so the disabled-history variant skips cleanly.



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