[jira] [Commented] (KAFKA-12462) Threads in PENDING_SHUTDOWN entering a rebalance can cause an illegal state exception

["A. Sophie Blee-Goldman (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/KAFKA-12462?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17300650#comment-17300650 ] 

A. Sophie Blee-Goldman commented on KAFKA-12462:
------------------------------------------------

Thanks Walker! This actually seems like a long-lurking bug that was just surfaced by the removeStreamThread() feature, not caused by it. Before we could remove threads this was only possible when shutting down the client, which we don’t test as frequently as we now do removeStreamThread(). It’s also hard to notice that a bug has caused thread(s) to die when the threads were supposed to shut down anyways. But now we might only be removing one thread, and thanks to the new exception handler we’ll shut down the whole application upon hitting this so the thread won’t just quietly die.

We should consider backporting the fix to 2.7, even though the bug isn't going to be as frequent or as bad in earlier versions. I wouldn't cut a new RC for 2.6.2 over this, but we might as well backport to get the fix in 2.7.1 whenever that comes out

> Threads in PENDING_SHUTDOWN entering a rebalance can cause an illegal state exception 
> --------------------------------------------------------------------------------------
>
>                 Key: KAFKA-12462
>                 URL: https://issues.apache.org/jira/browse/KAFKA-12462
>             Project: Kafka
>          Issue Type: Bug
>            Reporter: Walker Carlson
>            Priority: Blocker
>             Fix For: 2.8.0
>
>
> A thread was removed, sending it to the PENDING_SHUTDOWN state, but went through a rebalance before completing the shutdown.
> {code:java}
> // [2021-03-07 04:33:39,385] DEBUG [i-07430efc31ad166b7-StreamThread-6] stream-thread [i-07430efc31ad166b7-StreamThread-6] Ignoring request to transit from PENDING_SHUTDOWN to PARTITIONS_REVOKED: only DEAD state is a valid next state (org.apache.kafka.streams.processor.internals.StreamThread)
> {code}
> Inside StreamsRebalanceListener#onPartitionsRevoked, we have
> {code:java}
> // 
> if (streamThread.setState(State.PARTITIONS_REVOKED) != null && !partitions.isEmpty())
>     taskManager.handleRevocation(partitions);
> {code}
> Since PENDING_SHUTDOWN → PARTITIONS_REVOKED is a disallowed transition, we never invoke TaskManager#handleRevocation. Currently handleRevocation is responsible for preparing any active tasks for close, including committing offsets and writing the checkpoint as well as suspending the task. We can’t close the task in handleRevocation since we still support EAGER rebalancing, which invokes handleRevocation at the beginning of a rebalance on all tasks.
> The tasks that are actually revoked will be closed during TaskManager#handleAssignment . The IllegalStateException is specifically because we don’t suspend the task before attempting to close it, and the direct transition from RUNNING → CLOSED is forbidden.



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