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https://issues.apache.org/jira/browse/FLINK-21351?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17282867#comment-17282867
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Yun Tang edited comment on FLINK-21351 at 2/11/21, 5:56 AM:
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[~dwysakowicz] yes, once a savepoint completed, the previous added incremental
checkpoint would be subsumed. If the job is cancelled and savepoint would be
used to restore for next running, everything is fine. However, if the job is
still running and still depends on checkpoint mechanism for failover, this
would cause unrecoverable data lost.
was (Author: yunta):
[~dwysakowicz] yes, once a savepoint completed, the previous added incremental
checkpoint would be subsumed. If the job is cancelled and savepoint would be
used to restore for next running, everything is fine. However, if the job is
still running and still depend checkpoint mechanism for failover, this would
cause unrecoverable data lost.
> Incremental checkpoint data would be lost once a non-stop savepoint completed
> -----------------------------------------------------------------------------
>
> Key: FLINK-21351
> URL: https://issues.apache.org/jira/browse/FLINK-21351
> Project: Flink
> Issue Type: Bug
> Components: Runtime / Checkpointing
> Affects Versions: 1.11.3, 1.12.1, 1.13.0
> Reporter: Yun Tang
> Priority: Blocker
> Fix For: 1.11.4, 1.12.2, 1.13.0
>
>
> FLINK-10354 counted savepoint as retained checkpoint so that job could
> failover from latest position. I think this operation is reasonable, however,
> current implementation would let incremental checkpoint data lost immediately
> once a non-stop savepoint completed.
> Current general phase of incremental checkpoints: once a newer checkpoint
> completed, it would be added to checkpoint store. And if the size of
> completed checkpoints larger than max retained limit, it would subsume the
> oldest one. This lead to the reference of incremental data decrease one and
> data would be deleted once reference reached to zero. As we always ensure to
> register newer checkpoint and then unregister older checkpoint, current phase
> works fine as expected.
> However, if a non-stop savepoint (a median manual trigger savepoint) is
> completed, it would be also added into checkpoint store and just subsume
> previous added checkpoint (in default retain one checkpoint case), which
> would unregister older checkpoint without newer checkpoint registered,
> leading to data lost.
> Thanks for [~banmoy] reporting this problem first.
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