hadoop-hive-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Zheng Shao (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HIVE-1194) sorted merge join
Date Thu, 25 Feb 2010 01:22:28 GMT

    [ https://issues.apache.org/jira/browse/HIVE-1194?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12838132#action_12838132
] 

Zheng Shao commented on HIVE-1194:
----------------------------------

If it does not inherit any methods, shall we add an AbstractMapJoinOperator as the common
parent?
That AbstractMapJoinOperator can be converted to MapJoinOperator (or HashBasedMapJoinOperator,
to be accurate) or SortMergeJoinOperator depending on the configuration/table properties.


> sorted merge join
> -----------------
>
>                 Key: HIVE-1194
>                 URL: https://issues.apache.org/jira/browse/HIVE-1194
>             Project: Hadoop Hive
>          Issue Type: New Feature
>          Components: Query Processor
>            Reporter: Namit Jain
>            Assignee: He Yongqiang
>             Fix For: 0.6.0
>
>
> If the input tables are sorted on the join key, and a mapjoin is being performed, it
is useful to exploit the sorted properties of the table.
> This can lead to substantial cpu savings - this needs to work across bucketed map joins
also.
> Since, sorted properties of a table are not enforced currently, a new parameter can be
added to specify to use the sort-merge join.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


Mime
View raw message