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From "James Taylor (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (PHOENIX-852) Optimize child/parent foreign key joins
Date Wed, 27 Aug 2014 17:51:58 GMT

    [ https://issues.apache.org/jira/browse/PHOENIX-852?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14112540#comment-14112540
] 

James Taylor commented on PHOENIX-852:
--------------------------------------

Good point. You'll need to sort the join key on PK position, but not do anything else. The
WhereOptimizer will do the rest for you.

> Optimize child/parent foreign key joins
> ---------------------------------------
>
>                 Key: PHOENIX-852
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-852
>             Project: Phoenix
>          Issue Type: Improvement
>            Reporter: James Taylor
>            Assignee: Maryann Xue
>         Attachments: 852-2.patch, 852.patch, PHOENIX-852.patch
>
>
> Often times a join will occur from a child to a parent. Our current algorithm would do
a full scan of one side or the other. We can do much better than that if the HashCache contains
the PK (or even part of the PK) from the table being joined to. In these cases, we should
drive the second scan through a skip scan on the server side.



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