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https://issues.apache.org/jira/browse/HBASE-8316?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13628441#comment-13628441
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Lars Hofhansl commented on HBASE-8316:
--------------------------------------
In TestJoinedScanner I tried with 1k and 128k large CFs.
For the Phoenix test:
* The small CF has one column of 8 bytes
* the large CF has three columns (200 bytes, 200 bytes, 8 bytes - 408 bytes in
total)
> JoinedHeap for non essential column families should reseek instead of seek
> --------------------------------------------------------------------------
>
> Key: HBASE-8316
> URL: https://issues.apache.org/jira/browse/HBASE-8316
> Project: HBase
> Issue Type: Sub-task
> Components: Filters, Performance, regionserver
> Reporter: Lars Hofhansl
> Assignee: Lars Hofhansl
> Fix For: 0.98.0, 0.94.7, 0.95.1
>
> Attachments: 8316-0.94.txt, 8316-trunk.txt, 8316-trunk.txt,
> FDencode.png, noencode.png
>
>
> This was raised by the Phoenix team. During a profiling session we noticed
> that catching the joinedHeap up to the current rows via seek causes a
> performance regression, which makes the joinedHeap only efficient when either
> a high or low percentage is matched by the filter.
> (High is fine, because the joinedHeap will not get behind as often and does
> not need to be caught up, low is fine, because the seek isn't happening
> frequently).
> In our tests we found that the solution is quite simple: Replace seek with
> reseek. Patch coming soon.
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