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https://issues.apache.org/jira/browse/SAMZA-1012?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15546936#comment-15546936
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Navina Ramesh commented on SAMZA-1012:
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[~twbecker] Does this change affect existing job? What happens when they
upgrade? Does it mess up the mapping for these jobs ?
> Generated changelog mappings are not consistent
> -----------------------------------------------
>
> Key: SAMZA-1012
> URL: https://issues.apache.org/jira/browse/SAMZA-1012
> Project: Samza
> Issue Type: Bug
> Affects Versions: 0.10.1
> Reporter: Tommy Becker
> Assignee: Tommy Becker
> Attachments: 0001-Fix-SAMZA-1012.patch
>
>
> Samza generates a changelog partition mapping for stateful jobs the first
> time the job is started. The mapping is then persisted in the coordinator
> stream. However, the way the mapping is generated does not guarantee the same
> mapping will always be produced for the same inputs. Although this is not
> strictly necessary (since the mapping is persisted) it can help in certain
> situations. This bit us recently when we lost the contents of a checkpoint
> topic. The job generated a new and different changelog mapping when restarted
> and began producing very strange results which took a lot of effort to track
> down.
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