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From "James Taylor (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (PHOENIX-852) Optimize child/parent foreign key joins
Date Mon, 01 Sep 2014 17:59:20 GMT

    [ https://issues.apache.org/jira/browse/PHOENIX-852?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14117603#comment-14117603
] 

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

I see. Note that for VARCHAR and VARBINARY, the maxLength is the max size of the value so
I doubt you'd need to use it for those types. Any way, this all looks very good, so please
commit it when you're ready.

> 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, 852-3.patch, 852-4.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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