[jira] [Commented] (HIVE-2116) Optimize map-side scans for right-side of join

["Ron Bodkin (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-2116?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13020701#comment-13020701 ] 

Ron Bodkin commented on HIVE-2116:
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Table b was an HBase table, rather than a traditional HDFS file, if that is relevant to the issue.

> Optimize map-side scans for right-side of join
> ----------------------------------------------
>
>                 Key: HIVE-2116
>                 URL: https://issues.apache.org/jira/browse/HIVE-2116
>             Project: Hive
>          Issue Type: Improvement
>            Reporter: Ron Bodkin
>
> I had a large query like select * from a join b on a.key=b.key where...; 
> Table b was too large, so I attempted to optimize by adding constraints on b to the where clause, e.g.,
> where b.size>=mn and b.size<=mx and ...;
> However, the Hive 0.8.0 optimizer pushed the constraint on b into the reduce phase (defeating its purpose).
> I was able to force Hive to run the optimization map-side by this workaround:
> join (select * from b where size>=mn and size<=mx) b on a.key=b.key where ...;
> But it would be nice for Hive to pull filters on joined records into the map phase where possible. 

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