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https://issues.apache.org/jira/browse/FLINK-29856?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17638394#comment-17638394
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Mason Chen edited comment on FLINK-29856 at 11/24/22 6:44 PM:
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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, trigger intermediate Savepoint has the 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).
---
For the purposes of being backward compatible, does it make sense to enable the
notifyCheckpointComplete behavior in intermediate savepoints for 1.16 and
remove it when https://issues.apache.org/jira/browse/FLINK-29634 is released in
1.17?
was (Author: mason6345):
[~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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