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https://issues.apache.org/jira/browse/HUDI-7671?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17841012#comment-17841012
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Danny Chen commented on HUDI-7671:
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Another solution is we rename the completed meta files in the upgrade procedure.
> Make Hudi timeline backward compatible
> --------------------------------------
>
> Key: HUDI-7671
> URL: https://issues.apache.org/jira/browse/HUDI-7671
> Project: Apache Hudi
> Issue Type: Improvement
> Components: core
> Reporter: Danny Chen
> Assignee: Danny Chen
> Priority: Major
> Labels: compatibility
> Fix For: 1.0.0
>
>
> Since release 1.x, the timeline metadata file name is changed to include the
> completion time, we need to keep compatibility for 0.x branches/releases.
> 0.x meta file name pattern: ${instant_time}.action[.state]
> 1.x meta file name pattern: ${instant_time}_${completion_time}.action[.state].
> In 1.x release, while decipher the Hudi instant from the metadata files, if
> there is no completion time, uses the file modification time as the
> completion time instead.
> The modification time follows the OCC concurrency control semantics if the
> files were not moved around.
> Caution that if the table is a MOR table and the files got moved in history
> from old folder to the current folder, the reader view may represent wong
> result set because the completion time are completely the same for all the
> alive instants.
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