hive-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Yin Huai (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-3086) Skewed Join Optimization
Date Tue, 18 Sep 2012 16:46:08 GMT

    [ https://issues.apache.org/jira/browse/HIVE-3086?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13457939#comment-13457939
] 

Yin Huai commented on HIVE-3086:
--------------------------------

@Nadeem: Thanks! Just found another question. It seems that the large table (which has the
skewed keys) will be scanned twice. Is my understanding correct?
                
> Skewed Join Optimization
> ------------------------
>
>                 Key: HIVE-3086
>                 URL: https://issues.apache.org/jira/browse/HIVE-3086
>             Project: Hive
>          Issue Type: New Feature
>          Components: Query Processor
>            Reporter: Nadeem Moidu
>            Assignee: Namit Jain
>             Fix For: 0.10.0
>
>         Attachments: hive.3086.1.patch, hive.3086.2.patch, hive.3086.3.patch, hive.3086.4.patch,
hive.3086.5.patch, hive.3086.6.patch
>
>
> During a join operation, if one of the columns has a skewed key, it can cause that particular
reducer to become the bottleneck. The following feature will address it:
> https://cwiki.apache.org/confluence/display/Hive/Skewed+Join+Optimization

--
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