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Posted to issues@hbase.apache.org by "Ted Yu (JIRA)" <ji...@apache.org> on 2016/08/01 00:45:20 UTC

[jira] [Commented] (HBASE-16296) Reverse scan performance degrades when scanner cache size matches page filter size

    [ https://issues.apache.org/jira/browse/HBASE-16296?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15401409#comment-15401409 ] 

Ted Yu commented on HBASE-16296:
--------------------------------

As Lars acknowledged, since his patch did change the behavior of FilterList, I feel we can adopt change which doesn't change the behavior.

The filterAllRemaining() call is an optimization. If it is removed, there would be regression in performance.

> Reverse scan performance degrades when scanner cache size matches page filter size
> ----------------------------------------------------------------------------------
>
>                 Key: HBASE-16296
>                 URL: https://issues.apache.org/jira/browse/HBASE-16296
>             Project: HBase
>          Issue Type: Bug
>            Reporter: James Taylor
>         Attachments: 16296-MAYBE.txt, generatedata-snippet.java, repro-snippet.java
>
>
> When a reverse scan is done, the server seems to not know it's done when the scanner cache size matches the number of rows in a PageFilter. See PHOENIX-3121 for how this manifests itself. We have a standalone, pure HBase API reproducer too that I'll attach (courtesy of [~churromorales] and [~mujtabachohan]).



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