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Posted to dev@phoenix.apache.org by "James Taylor (JIRA)" <ji...@apache.org> on 2014/08/21 05:46:26 UTC

[jira] [Resolved] (PHOENIX-1192) Re-enable reverse scan to prevent order by

     [ https://issues.apache.org/jira/browse/PHOENIX-1192?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

James Taylor resolved PHOENIX-1192.
-----------------------------------

       Resolution: Fixed
    Fix Version/s: 4.1
                   5.0.0

> Re-enable reverse scan to prevent order by
> ------------------------------------------
>
>                 Key: PHOENIX-1192
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-1192
>             Project: Phoenix
>          Issue Type: Bug
>    Affects Versions: 5.0.0, 4.1
>            Reporter: James Taylor
>             Fix For: 5.0.0, 4.1
>
>         Attachments: PHOENIX-1192.patch
>
>
> We have code in place and tested for usage of the reverse scan. It's just turned off because the reverse scan ability never made it to 0.94. Now that we have 4.x on top of 0.98, we should turn this back on. It's used to optimize queries that do an ORDER BY in the descending order of the PK (to prevent the standard and expensive order by processing). Prior tests have shown a dramatic difference between the two ways of executing the query.



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