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https://issues.apache.org/jira/browse/KYLIN-2926?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16213750#comment-16213750
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liyang commented on KYLIN-2926:
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As mentioned in KYLIN-2944, I do have concern here. The sharing of object is
for performance sake, the same reason as Mapper and Reducer reusing objects in
their interfaces.
I'm doing a quick benchmark to see the performance difference.
> DumpMerger return incorrect results
> -----------------------------------
>
> Key: KYLIN-2926
> URL: https://issues.apache.org/jira/browse/KYLIN-2926
> Project: Kylin
> Issue Type: Bug
> Affects Versions: v2.0.0
> Reporter: fengYu
> Assignee: fengYu
> Attachments:
> 0001-KYLIN-2926-DumpMerger-return-incorrect-results-creat.patch
>
>
> I our scenario, a cube query will get wrong result once coprocessor need to
> spill to disk, Our version is 2.0.0 and I find the root cause is that in
> DumpMerger.enqueueFromDump
> because in DataTypeSerializer kylin use a ThreadLocal variable ‘current’, It
> leading to different elements in dumpCurrentValues share the same object, so
> next fill up measure values will change the existing values.
> the incorrect measures is HLLC and raw, which use current variable in
> deserialize.
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