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https://issues.apache.org/jira/browse/AURORA-1674?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15255452#comment-15255452
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Bill Farner commented on AURORA-1674:
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Noticed this thread on the h2 users list that might prove relevant:
https://groups.google.com/forum/#!topic/h2-database/T0ZLmPucUAo
No resolution on that thread yet, but you should follow along and consider
pitch in profiling data. If you manage to reproduce locally, it would be
really interesting to compare against 1.3.176.
> Migration from MemTaskStore to DbTaskStore can take hours
> ---------------------------------------------------------
>
> Key: AURORA-1674
> URL: https://issues.apache.org/jira/browse/AURORA-1674
> Project: Aurora
> Issue Type: Bug
> Reporter: Zameer Manji
>
> Migrating an Aurora instance which has about 330k tasks in MemTaskStore to
> DbTaskStore took over 13h.
> This can be replicated as follows:
> # Schedule thousands of tasks with a scheduler on MemTaskStore
> # Use {{aurora_admin}} to create a snapshot.
> # Redeploy the scheduler with DbTaskStore enabled
> # Watch as Snapshot recovery and inserting tasks takes several hours
> Stack dumps of this process indicates that all of the time was spent in H2
> handing the consequences of inserting hundreds of thousands of records.
> I wasn't able to figure out what precisely was the root cause but here are
> some possible suspects
> * Generating the SQL for delete tasks which would involve creating a delete
> statement with 330k task ids.
> * H2 transaction/locking configuration making this mass insert very slow.
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