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From "Jesus Camacho Rodriguez (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-11684) Implement limit pushdown through outer join in CBO
Date Thu, 10 Sep 2015 07:36:45 GMT

    [ https://issues.apache.org/jira/browse/HIVE-11684?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14738339#comment-14738339
] 

Jesus Camacho Rodriguez commented on HIVE-11684:
------------------------------------------------

[~sershe], I had not seen that issue, but the goal is the same. However, it seems no work
has been done in HIVE-11530.

As you know, currently we do not hit the CBO path for such simple queries, so the new rule
will not be applied in those cases.
IMO we should not be implementing these optimizations twice i.e. in Hive and Calcite/CBO,
which has happened before. I think we should be able to always go through CBO path for query
optimization; we need to study where the specific overhead comes from, and either 1) reduce
it if it is related to bad design/engineering, or 2) disable some of the most advanced features
for those simple queries.

> Implement limit pushdown through outer join in CBO
> --------------------------------------------------
>
>                 Key: HIVE-11684
>                 URL: https://issues.apache.org/jira/browse/HIVE-11684
>             Project: Hive
>          Issue Type: New Feature
>          Components: CBO
>    Affects Versions: 2.0.0
>            Reporter: Jesus Camacho Rodriguez
>            Assignee: Jesus Camacho Rodriguez
>         Attachments: HIVE-11684.01.patch, HIVE-11684.02.patch, HIVE-11684.03.patch, HIVE-11684.04.patch,
HIVE-11684.patch
>
>




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