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https://issues.apache.org/jira/browse/FLINK-37979?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17985220#comment-17985220
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Sergei Morozov commented on FLINK-37979:
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I've already submitted a PR for this one:
[apache/flink-cdc#4048|https://github.com/apache/flink-cdc/pull/4048].
> Obsolete MySQL CDC snapshot split assigner code
> -----------------------------------------------
>
> Key: FLINK-37979
> URL: https://issues.apache.org/jira/browse/FLINK-37979
> Project: Flink
> Issue Type: Technical Debt
> Components: Flink CDC
> Affects Versions: cdc-3.4.0
> Reporter: Sergei Morozov
> Priority: Minor
>
> There is a redundant condition and a misleading comment in
> {{MySqlSnapshotSplitAssigner#captureNewlyAddedTables()}} that complicate
> understanding of the code.
> The condition {{if (AssignerStatus.isAssigningFinished(assignerStatus))}} is
> evaluated twice in the method in question: once in the very beginning and
> once closer to the end. This way, the second evaluation will always result in
> {{true}} and thus is redundant.
> h3. Code Change History
> Prior to FLINK-35859, table discovery would happen in any assigner status, so
> the condition in the end of the method made sense. Together with adding this
> condition in the beginning of the method, FLINK-35859 should have removed it
> from the end.
> h3. What Exactly is Obsolete
> # There is a comment saying "if job is still in snapshot reading phase,
> directly add all newly added tables". Since FLINK-35859, if the job is still
> in the snapshot reading phase, this code won't be executed. This comment
> should be removed as misleading.
> # The second {{if (AssignerStatus.isAssigningFinished(assignerStatus))}}
> statement. While the {{captureNewlyAddedTables()}} method is running, the
> assigner status cannot be modified by a different thread because this code is
> only executed as part of {{MySqlSourceEnumerator#open()}}, i.e. the source in
> its initialization phase.
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