[jira] [Comment Edited] (HIVE-16298) Add config to specify multi-column joins have correlated columns

["Lefty Leverenz (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-16298?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15942194#comment-15942194 ] 

Lefty Leverenz edited comment on HIVE-16298 at 9/21/17 3:13 AM:
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[~jdere], since this was committed to master after branch-2 split off on March 23 (11:06pm PDT) the fix version should say 3.0.0.  If you want it in 2.3.0 commit it to branch-2.  For 2.2.0 commit to branch-2.2.

Nudge (edit 20/Sep/17):  This is in master for release 3.0.0 but not in branch-2.3 for 2.3.0, nor branch-2 for 2.4.0.  So the fix version should be changed from 2.3.0 to 3.0.0.


was (Author: lefty@hortonworks.com):
[~jdere], since this was committed to master after branch-2 split off on March 23 (11:06pm PDT) the fix version should say 3.0.0.  If you want it in 2.3.0 commit it to branch-2.  For 2.2.0 commit to branch-2.2.

> Add config to specify multi-column joins have correlated columns
> ----------------------------------------------------------------
>
>                 Key: HIVE-16298
>                 URL: https://issues.apache.org/jira/browse/HIVE-16298
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Jason Dere
>            Assignee: Siddharth Seth
>              Labels: TODOC3.0
>             Fix For: 2.3.0
>
>         Attachments: HIVE-16298.1.patch, HIVE-16298.2.patch
>
>
> The default row estimation for multi-key joins divides the row estimate by the product of the NDVs for each join column, which can cause the row estimate to be low. Try adding a config to assume the columns are correlated, where we only divide the row estimate by the largest NDV.



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