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Posted to issues@flink.apache.org by "Hangxiang Yu (Jira)" <ji...@apache.org> on 2022/03/15 02:45:00 UTC
[jira] [Commented] (FLINK-23252) Support recovery (from checkpoints) after disabling changelog backend
[ https://issues.apache.org/jira/browse/FLINK-23252?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17506668#comment-17506668 ]
Hangxiang Yu commented on FLINK-23252:
--------------------------------------
I'd like to work on it. Would you mind to assign this ticket to me? Thanks. [~roman]
> Support recovery (from checkpoints) after disabling changelog backend
> ---------------------------------------------------------------------
>
> Key: FLINK-23252
> URL: https://issues.apache.org/jira/browse/FLINK-23252
> Project: Flink
> Issue Type: Sub-task
> Components: Runtime / State Backends
> Reporter: Roman Khachatryan
> Priority: Major
> Fix For: 1.16.0
>
>
> Recovery from savepoint already works:
> * changelog off -> on: FLINK-23278
> * changelog on -> off: directly calling {{{}underlyingBackend.{}}}{{{}savepoint{}}}{{{}(){}}} (instead of {{{}writer.persist(){}}})
>
> For checkpoints, changelog on -> off doesn't work. Regular state backend will receive materialized and non-aterialized state on recovery. To support it, state changes have to be applied on recovery even if changelog backend is disabled.
> Another obstacle could be that wrapped backend state handles created during materialization can refer to a fake checkpoint ID. This fake checkpoint ID would then be passed to e.g. RocksIncrementalSnapshotStrategy on restore.
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