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https://issues.apache.org/jira/browse/PHOENIX-852?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14105467#comment-14105467
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Maryann Xue commented on PHOENIX-852:
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Since using skip scan or range scan in joins largely depends on the RHS table
data and plus we can have stats to do pretty good judgement later on, I do
prefer having a separate set of hints and independent code logic for this use.
So is it good enough that by default we do BETWEEN-AND for full key match (e.g.
c1,c2,c3 matched in c1,c2,c3), but only IN clause if the SKIP_SCAN_HASH_JOIN
hint is on; and by default do IN clause for partial key match (e.g. c1,c2
matched in c1,c2,c3), but only BETWEEN-AND clause if RANGE_SCAN_HASH_JOIN hint
is on?
> 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.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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