hive-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Namit Jain (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-3403) user should not specify mapjoin to perform sort-merge bucketed join
Date Thu, 18 Oct 2012 19:16:04 GMT

    [ https://issues.apache.org/jira/browse/HIVE-3403?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13479263#comment-13479263
] 

Namit Jain commented on HIVE-3403:
----------------------------------

Had an offline review with Kevin - the following came out of that:

1. The policy to choose the big table should take the average size of the partition into account.
   We dont need to change the existing policy, can add a new policy.
2. The new policy should give preference to a table with no partitions/ 1 partition.
3. If one of the tables is small enough to fit in memory, there is no need to perform sort-merge
join. The
   policy should check that. Eventually, that check should be removed, and that should be
handled by the physical
   optimizer - will file a new jira for that.

                
> user should not specify mapjoin to perform sort-merge bucketed join
> -------------------------------------------------------------------
>
>                 Key: HIVE-3403
>                 URL: https://issues.apache.org/jira/browse/HIVE-3403
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Namit Jain
>            Assignee: Namit Jain
>         Attachments: hive.3403.1.patch
>
>
> Currently, in order to perform a sort merge bucketed join, the user needs
> to set hive.optimize.bucketmapjoin.sortedmerge to true, and also specify the 
> mapjoin hint.
> The user should not specify any hints.

--
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

Mime
View raw message