[jira] [Commented] (HIVE-15771) CBO chooses wrong join order for TPC-DS query72

["Pengcheng Xiong (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-15771?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15941921#comment-15941921 ] 

Pengcheng Xiong commented on HIVE-15771:
----------------------------------------

I am deferring this to Hive 3.0 as we are going to cut the first RC and it is not marked as blocker. Please feel free to commit to the branch if this can be resolved before the release.

> CBO chooses wrong join order for TPC-DS query72
> -----------------------------------------------
>
>                 Key: HIVE-15771
>                 URL: https://issues.apache.org/jira/browse/HIVE-15771
>             Project: Hive
>          Issue Type: Bug
>          Components: CBO
>    Affects Versions: 2.2.0
>            Reporter: Prasanth Jayachandran
>            Priority: Critical
>         Attachments: q72-explain.txt, q72-mod-explain.txt, q72-mod.svg, q72.svg, query72-mod.sql, query72.sql
>
>
> Query72 of TPC-DS on 1TB scale generates wrong join order resulting in increased query execution time. It chooses fact-to-fact table join followed by joins with dimension tables as opposed to doing map-join with dimension tables first and doing the fact-to-fact table join at the last.
> Please find attachment for the join order selected by CBO vs rewritten query with expected join order. 



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