[jira] [Commented] (FLINK-29856) Triggering savepoint does not trigger operator notifyCheckpointComplete

["Mason Chen (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-29856?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17638394#comment-17638394 ] 

Mason Chen commented on FLINK-29856:
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[~masteryhx] [~mxm] [~gaoyunhaii] I double checked that snapshotState **is** called, but notifyCheckpointComplete **is not**–this is observable from FLIP 27 sources and custom stateful UDFs. It looks like an intended design decision like Max mentioned.

> i.e. calling notifyCheckpointComplete() again for already processed records/state.

Yes, I noticed this odd side effect when I tried to fix this issue, but it could be alleviated by adding the check for if the job is restoring or not.

---

Without notifyCheckpointComplete, it isn't clear what the benefit of an intermediate Savepoint is (need to re-read the FLIP). From the user perspective, it was benefit to be able to commit data to external systems like Kafka/Iceberg on demand for their operational procedures. Perhaps, the eventual solution is to replace operational procedure with triggering checkpoint with https://issues.apache.org/jira/browse/FLINK-29634 since that would match the effects (notifyCheckpointComplete, etc).

> Triggering savepoint does not trigger operator notifyCheckpointComplete
> -----------------------------------------------------------------------
>
>                 Key: FLINK-29856
>                 URL: https://issues.apache.org/jira/browse/FLINK-29856
>             Project: Flink
>          Issue Type: Improvement
>          Components: Runtime / Checkpointing
>    Affects Versions: 1.16.0
>            Reporter: Mason Chen
>            Priority: Major
>
> When I trigger a savepoint with the Flink K8s operator, I verified for two sources (KafkaSource and MultiClusterKafkaSource) do not invoke notifyCheckpointComplete. This is easily reproducible in a simple pipeline (e.g. KafkaSource -> print). In this case, the savepoint is complete and successful, which is verified by the Flink Checkpoint UI tab and the jobmanager logs. e.g. `
> Triggering checkpoint 3 (type=SavepointType\{name='Savepoint', postCheckpointAction=NONE, formatType=CANONICAL})`
>  
> However, when the checkpoint occurs via the interval, I do see the sources checkpointing properly and expected logs in the output.
> After the ticket was initially filed, I also checked with other stateful UDFs and observed the same behavior.



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