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Date: Tue, 8 Jan 2013 12:14:17 +0000 (UTC)
From: "Phabricator (JIRA)" <jira@apache.org>
To: hive-dev@hadoop.apache.org
Message-ID: <JIRA.12611120.1349845960621.96604.1357647257653@arcas>
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Subject: [jira] [Commented] (HIVE-3562) Some limit can be pushed down to map
 stage
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    [ https://issues.apache.org/jira/browse/HIVE-3562?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13546822#comment-13546822 ] 

Phabricator commented on HIVE-3562:
-----------------------------------

navis has commented on the revision "HIVE-3562 [jira] Some limit can be pushed down to map stage".

  I think I'm wrong about GBY cases. Should be fixed definitely (in next week, maybe).

REVISION DETAIL
  https://reviews.facebook.net/D5967

To: JIRA, tarball, navis
Cc: njain

                
> Some limit can be pushed down to map stage
> ------------------------------------------
>
>                 Key: HIVE-3562
>                 URL: https://issues.apache.org/jira/browse/HIVE-3562
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Navis
>            Assignee: Navis
>            Priority: Trivial
>         Attachments: HIVE-3562.D5967.1.patch, HIVE-3562.D5967.2.patch, HIVE-3562.D5967.3.patch
>
>
> Queries with limit clause (with reasonable number), for example
> {noformat}
> select * from src order by key limit 10;
> {noformat}
> makes operator tree, 
> TS-SEL-RS-EXT-LIMIT-FS
> But LIMIT can be partially calculated in RS, reducing size of shuffling.
> TS-SEL-RS(TOP-N)-EXT-LIMIT-FS

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