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From "Prasanth Jayachandran (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-15771) CBO chooses wrong join order for TPC-DS query72
Date Tue, 31 Jan 2017 23:14:51 GMT

    [ https://issues.apache.org/jira/browse/HIVE-15771?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15847698#comment-15847698
] 

Prasanth Jayachandran commented on HIVE-15771:
----------------------------------------------

cc/ [~ashutoshc] [~jcamachorodriguez] [~pxiong]

> 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 correct
join order. 



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