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https://issues.apache.org/jira/browse/SPARK-59972?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated SPARK-59972:
-----------------------------------
Labels: pull-request-available (was: )
> Dynamic allocation can stall after an unfinished task is killed
> ---------------------------------------------------------------
>
> Key: SPARK-59972
> URL: https://issues.apache.org/jira/browse/SPARK-59972
> Project: Spark
> Issue Type: Bug
> Components: Spark Core
> Affects Versions: 4.3.0
> Reporter: MJ Deng
> Priority: Major
> Labels: pull-request-available
>
> ExecutorAllocationManager does not count an unfinished regular task as
> pending again when its running attempt is explicitly killed.
> A possible event sequence is:
> # A task starts on an available executor while the executor target is zero.
> # Starting the task drains the scheduler queue and clears the scheduler
> backlog timer.
> # SparkContext.killTaskAttempt kills the task before it succeeds.
> # The scheduler requeues the unfinished task.
> # ExecutorAllocationListener.onTaskEnd ignores TaskKilled, so it does not
> mark the task as pending or restart the backlog timer.
> # If the available executor is subsequently lost before the task relaunches,
> dynamic allocation does not request a replacement executor and the stage can
> stall.
> TaskKilled cannot always be treated as pending because a regular attempt may
> be killed after a speculative copy has already succeeded, as covered by
> SPARK-30511.
> The listener should therefore count a killed regular task as pending and
> restart the backlog timer only when:
> * the stage attempt is still active;
> * the killed attempt is non-speculative;
> * the task index has not already succeeded; and
> * the task index was known to be running.
> Killed speculative attempts and task-end events from completed stages should
> remain
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