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https://issues.apache.org/jira/browse/HIVE-279?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12693975#action_12693975
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Ashish Thusoo commented on HIVE-279:
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+1
Looks good to me.
A few things to watch out for before you upload the complete patch..
1. ppd_gby_join.q is missing.
2. Would be great to have a join test case where the left and right ourter
joins are part of the same join operator.
3. Also would be great to have a join test case where there is a three way join
and the join operators do not merge.
4. Also a test case with UDFs (not the rand one) that gets pushed down would
also be awesome.
Otherwise looks quite cool to me.
> 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.
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