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https://issues.apache.org/jira/browse/OMID-145?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16818690#comment-16818690
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Yonatan Gottesman commented on OMID-145:
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[~lhofhansl] maybe this is a rare situation like Ohad explained but it wont
hurt to have a small (limited sized) cache
I added a patch see if its better now with your example
> High CPU usage during compactions.
> ----------------------------------
>
> Key: OMID-145
> URL: https://issues.apache.org/jira/browse/OMID-145
> Project: Apache Omid
> Issue Type: Bug
> Reporter: Lars Hofhansl
> Priority: Major
> Fix For: 1.0.1
>
> Attachments: compactionTiming.png
>
>
> See attached image, almost all (96%!!) of the compaction time is spent in
> org.apache.hadoop.hbase.regionserver.CompactorScanner.queryCommitTimestamp()
> I guess that's when the shadowCell is not yet present.
> We already have problems with long compactions in HBase, prolonging these
> potentially by 25x (all the rest of the compaction logic took only 4% of the
> time), would not be a pleasant idea.
> Perhaps we can do that same caching we do with the commit cache during
> regular scanning...?
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