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https://issues.apache.org/jira/browse/PHOENIX-852?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14111140#comment-14111140
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Maryann Xue commented on PHOENIX-852:
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With more than one qualified join key, like pkCol0 and pkCol1, what I'm trying
to do is not "where pkCol0 in ... and pkCol1 in ..." but instead "where
(pkCol0, pkCol) in ...". These two are different, and with the first where
clause, there would be a lot of meaningless point lookups. But I don't think
RowValueConstructor can handle unordered key parts, like (pkCol1, pkCol0). Am I
right?
> 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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