hadoop-hive-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Prasad Chakka (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HIVE-279) Implement predicate push down for hive queries
Date Tue, 31 Mar 2009 04:19:50 GMT

    [ https://issues.apache.org/jira/browse/HIVE-279?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12693984#action_12693984
] 

Prasad Chakka commented on HIVE-279:
------------------------------------

1) I missed that file in the patch
2) Will add it
3) This test case is already there (ppd_join2.q or ppd_join3.q)
4) Will add it, but aren't all operators UDFs? 

> Implement predicate push down for hive queries
> ----------------------------------------------
>
>                 Key: HIVE-279
>                 URL: https://issues.apache.org/jira/browse/HIVE-279
>             Project: Hadoop Hive
>          Issue Type: New Feature
>          Components: Query Processor
>    Affects Versions: 0.2.0
>            Reporter: Prasad Chakka
>            Assignee: Prasad Chakka
>         Attachments: hive-279.2.patch, hive-279.3.patch, hive-279.4.patch, hive-279.5.patch,
hive-279.patch
>
>
> Push predicates that are expressed in outer queries into inner queries where possible
so that rows will get filtered out sooner.
> eg.
> select a.*, b.* from a join b on (a.uid = b.uid) where a.age = 20 and a.gender = 'm'
> current compiler generates the filter predicate in the reducer after the join so all
the rows have to be passed from mapper to reducer. by pushing the filter predicate to the
mapper, query performance should improve.

-- 
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