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From "Lars Hofhansl (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-9751) Excessive readpoints checks in StoreFileScanner
Date Sat, 12 Oct 2013 22:38:42 GMT

    [ https://issues.apache.org/jira/browse/HBASE-9751?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13793510#comment-13793510
] 

Lars Hofhansl commented on HBASE-9751:
--------------------------------------

Created HBASE-9753 for the MemstoreScanner improvements.

> Excessive  readpoints checks in StoreFileScanner
> ------------------------------------------------
>
>                 Key: HBASE-9751
>                 URL: https://issues.apache.org/jira/browse/HBASE-9751
>             Project: HBase
>          Issue Type: Bug
>    Affects Versions: 0.98.0, 0.94.12, 0.96.0
>            Reporter: Vladimir Rodionov
>            Assignee: Lars Hofhansl
>             Fix For: 0.98.0, 0.94.13, 0.96.1
>
>         Attachments: 9751-0.94.txt, 9751-trunk.txt
>
>
> It seems that usage of skipKVsNewerThanReadpoint in StoreFileScanner can be greatly reduced
or even eliminated all together (HFiles are immutable and no new KVs can be inserted after
scanner instance is created). The same is true for MemStoreScanner which checks readpoint
on every next() and seek(). Each readpoint check is ThreadLocal.get() and it is quite expensive.
 



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