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https://issues.apache.org/jira/browse/HBASE-14489?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14909088#comment-14909088
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Lars Hofhansl commented on HBASE-14489:
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By the way, testing this with Phoenix, which does add a coprocessor to each
table... A query that filters most rows out I also see a ~2.5x performance
improvement.
> postScannerFilterRow consumes a lot of CPU
> ------------------------------------------
>
> Key: HBASE-14489
> URL: https://issues.apache.org/jira/browse/HBASE-14489
> Project: HBase
> Issue Type: Bug
> Reporter: Lars Hofhansl
> Assignee: Lars Hofhansl
> Labels: performance
> Fix For: 2.0.0, 1.2.0, 1.3.0, 0.98.15, 1.0.3, 1.1.3
>
> Attachments: 14489-0.98.txt
>
>
> During an unrelated test I found that when scanning a tall table with CQ only
> and filtering most results at the server, 50%(!) of time is spend in
> postScannerFilterRow, even though the coprocessor does nothing in that hook.
> We need to find a way not to call this hook when not needed, or to question
> why we have this hook at all.
> I think [~ram_krish] added the hook (or maybe [~anoop.hbase]). I am also not
> sure whether Phoenix uses this hook ([~giacomotaylor]?)
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