You are viewing a plain text version of this content. The canonical link for it is here.
Posted to dev@hive.apache.org by "Navis (JIRA)" <ji...@apache.org> on 2012/10/08 09:24:03 UTC
[jira] [Commented] (HIVE-3550) Early skipping for limit operator at
reduce stage
[ https://issues.apache.org/jira/browse/HIVE-3550?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13471431#comment-13471431 ]
Navis commented on HIVE-3550:
-----------------------------
https://reviews.facebook.net/D5943
> Early skipping for limit operator at reduce stage
> -------------------------------------------------
>
> Key: HIVE-3550
> URL: https://issues.apache.org/jira/browse/HIVE-3550
> Project: Hive
> Issue Type: Improvement
> Components: Query Processor
> Reporter: Navis
> Assignee: Navis
> Priority: Trivial
> Attachments: HIVE-3550.D5943.1.patch
>
>
> Queries with limit clause whose final result is from reduce stage could not be early exited like map stage. But it seemed possible to just skip remaining lines. It can be accomplished by adding just two lines. Is there any reason we should not to do that?
> {noformat}
> select key from src order by key limit 10;
> 1. current
> ExtractOperator: 3 forwarded 500 rows
> LimitOperator: 4 forwarded 10 rows
> 2. early skipping
> ExtractOperator: 3 forwarded 12 rows
> LimitOperator: 4 forwarded 10 rows
> {noformat}
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira