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https://issues.apache.org/jira/browse/HIVE-17493?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Vineet Garg updated HIVE-17493:
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Status: Open (was: Patch Available)
> Improve PKFK cardinality estimation in Physical planning
> --------------------------------------------------------
>
> Key: HIVE-17493
> URL: https://issues.apache.org/jira/browse/HIVE-17493
> Project: Hive
> Issue Type: Improvement
> Components: Query Planning
> Reporter: Vineet Garg
> Assignee: Vineet Garg
> Attachments: HIVE-17493.1.patch, HIVE-17493.2.patch
>
>
> Cardinality estimation of a join, after PK-FK relation has been ascertained,
> could be improved if parent of the join operator is LEFT outer or RIGHT outer
> join.
> Currently estimation is done by estimating reduction of rows occurred on PK
> side, then multiplying the reduction to FK side row count. This estimation of
> reduction currently doesn't distinguish b/w INNER or OUTER joins. This could
> be improved to handle outer joins better.
> TPC-DS query45 is impacted by this.
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