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Posted to issues@hbase.apache.org by "Lars Hofhansl (JIRA)" <ji...@apache.org> on 2016/03/13 23:03:33 UTC

[jira] [Updated] (HBASE-15452) Consider removing checkScanOrder from StoreScanner.next

     [ https://issues.apache.org/jira/browse/HBASE-15452?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Lars Hofhansl updated HBASE-15452:
----------------------------------
    Attachment: 15452-0.98.txt

Patch... Just to park it. Simply removes the cruft.
Note that if we come in with identical KVs kvscanned will be off by those.


> Consider removing checkScanOrder from StoreScanner.next
> -------------------------------------------------------
>
>                 Key: HBASE-15452
>                 URL: https://issues.apache.org/jira/browse/HBASE-15452
>             Project: HBase
>          Issue Type: Bug
>            Reporter: Lars Hofhansl
>         Attachments: 15452-0.98.txt
>
>
> In looking why we spent so much time in StoreScanner.next when doing a simple Phoenix count\(*) query I came across checkScanOrder. Not only is this a function dispatch (that the JIT would eventually inline), it also requires setting the prevKV member for every Cell encountered.
> Removing that logic a yields measurable end-to-end improvement of 5-20% (in 0.98).
> I will repeat this test on my work machine tomorrow.
> I think we're stable enough to remove that check anyway.



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