[jira] [Commented] (FLINK-17351) CheckpointCoordinator and CheckpointFailureManager ignores checkpoint timeouts

["Yuan Mei (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-17351?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17111716#comment-17111716 ] 

Yuan Mei commented on FLINK-17351:
----------------------------------

 

Thanks for the pointers [~roman_khachatryan]. I have quite a nice walk ;)

I guess the fix is simple: increase `continuousFailureCounter` for exception `CHECKPOINT_EXPIRED` as well.

However, there is a list of checkpoint failure reasons listed (actually most of the reasons) are ignored.

Hence I am wondering what is the criteria for what should be ignored, and what should not?

> CheckpointCoordinator and CheckpointFailureManager ignores checkpoint timeouts
> ------------------------------------------------------------------------------
>
>                 Key: FLINK-17351
>                 URL: https://issues.apache.org/jira/browse/FLINK-17351
>             Project: Flink
>          Issue Type: Bug
>          Components: Runtime / Checkpointing
>    Affects Versions: 1.9.2, 1.10.0
>            Reporter: Piotr Nowojski
>            Priority: Critical
>             Fix For: 1.11.0
>
>
> As described in point 2: https://issues.apache.org/jira/browse/FLINK-17327?focusedCommentId=17090576&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-17090576
> (copy of description from above linked comment):
> The logic in how {{CheckpointCoordinator}} handles checkpoint timeouts is broken. In your [~qinjunjerry] examples, your job should have failed after first checkpoint failure, but checkpoints were time outing on CheckpointCoordinator after 5 seconds, before {{FlinkKafkaProducer}} was detecting Kafka failure after 2 minutes. Those timeouts were not checked against {{setTolerableCheckpointFailureNumber(...)}} limit, so the job was keep going with many timed out checkpoints. Now funny thing happens: FlinkKafkaProducer detects Kafka failure. Funny thing is that it depends where the failure was detected:
> a) on processing record? no problem, job will failover immediately once failure is detected (in this example after 2 minutes)
> b) on checkpoint? heh, the failure is reported to {{CheckpointCoordinator}} *and gets ignored, as PendingCheckpoint has already been discarded 2 minutes ago* :) So theoretically the checkpoints can keep failing forever and the job will not restart automatically, unless something else fails.
> Even more funny things can happen if we mix FLINK-17350 . or b) with intermittent external system failure. Sink reports an exception, transaction was lost/aborted, Sink is in failed state, but if there will be a happy coincidence that it manages to accept further records, this exception can be lost and all of the records in those failed checkpoints will be lost forever as well. In all of the examples that [~qinjunjerry] posted it hasn't happened. {{FlinkKafkaProducer}} was not able to recover after the initial failure and it was keep throwing exceptions until the job finally failed (but much later then it should have). And that's not guaranteed anywhere.



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