[
https://issues.apache.org/jira/browse/HIVE-17493?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Vineet Garg updated HIVE-17493:
-------------------------------
Attachment: HIVE-17493.3.patch
> 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,
> HIVE-17493.3.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.
--
This message was sent by Atlassian JIRA
(v6.4.14#64029)
