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

["Lars Hofhansl (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HBASE-16296?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Lars Hofhansl updated HBASE-16296:
----------------------------------
    Attachment: 16296-MAYBE-v2.txt

What about -v2?

Simply breaks early in RegionScannerImpl if the Filter would filterAllRemaining anyway.

Is that correct in all cases? Any scenarios where this would not work?
I confirmed that that fixes the Phoenix performance issue we've seen there.


> 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-v2.txt, 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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