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https://issues.apache.org/jira/browse/FLINK-26079?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17492441#comment-17492441
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Roman Khachatryan commented on FLINK-26079:
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> What I mean is: when we restore a job from a normal checkpoint (created by
>non-changelog state backend) and use changelog state backend with CLAIM mode,
>It's natural that we make/transfer the first checkpoint to a changelog-style
>checkpoint.
I think it is natural for TM (state backend) - and this is what it actually
does. But it is not natural for JM (checkpoint store), because it is not aware
of the changelog (and should not be in my opinion).
Implementation-wise, are you proposing to add a dependency on
ChangelogStateBackend to flink-runtime and run the necessary logic in JM inside
or around CompletedCheckpointStore?
Let's maybe move this discussion to FLINK-25872 which is about addressing the
original issue, not the enforcing the limitation?
> [Changelog] Disallow recovery from non-changelog checkpoints
> ------------------------------------------------------------
>
> Key: FLINK-26079
> URL: https://issues.apache.org/jira/browse/FLINK-26079
> Project: Flink
> Issue Type: Bug
> Components: Runtime / Configuration, Runtime / State Backends
> Reporter: Roman Khachatryan
> Assignee: Roman Khachatryan
> Priority: Blocker
> Labels: pull-request-available
> Fix For: 1.15.0
>
>
> Extracted from FLINK-25872.
> The issue is with the CLAIM mode:
> > Because discarding an initial checkpoint will invalidate its "private"
> > state which might be in use by future checkpoints.
> > Normally, changelog backend wraps it and registers with tjhe
> > SharedStateRegistry.
> > But when recovering from non-changelog checkpoint, it is first added to the
> > Checkpoint store, and wrapping in subsequent checkpoints doesn't help.
> NO_CLAIM mode is not supported.
> LEGACY could work.
> But it's difficult to differentiate between the modes on TM, where backend
> type is reliably known (see the discussion below).
> CANONICAL non-changelog savepoints must still be supported.
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