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https://issues.apache.org/jira/browse/HIVE-279?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Prasad Chakka updated HIVE-279:
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Attachment: hive-279.patch
this is a drop for initial review since i suspect there will be lot of comments
:). it should work for all cases except for multi-insert queries.
i have not enabled this by default but added a new config param called
hive.optimize.ppd to enable this feature.
i have not modified existing testcases but added couple of new testcases. will
add more while uploading final patch.
> 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
> Affects Versions: 0.2.0
> Reporter: Prasad Chakka
> Assignee: Prasad Chakka
> Attachments: 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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