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https://issues.apache.org/jira/browse/HIVE-2284?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13066080#comment-13066080
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jirapos...@reviews.apache.org commented on HIVE-2284:
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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/1136/
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Review request for hive and namit jain.
Summary
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Allow bucketed mapjoin if join key is a superset of bucket columns.
This addresses bug HIVE-2284.
https://issues.apache.org/jira/browse/HIVE-2284
Diffs
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trunk/contrib/build.xml 1146922
trunk/eclipse-templates/.classpath 1146922
trunk/ql/src/java/org/apache/hadoop/hive/ql/optimizer/BucketMapJoinOptimizer.java
1146922
trunk/ql/src/test/queries/clientpositive/smb_mapjoin_10.q PRE-CREATION
trunk/ql/src/test/results/clientpositive/smb_mapjoin_10.q.out PRE-CREATION
Diff: https://reviews.apache.org/r/1136/diff
Testing
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passed all unit tests.
Thanks,
Ning
> bucketized map join should allow join key as a superset of bucketized columns
> -----------------------------------------------------------------------------
>
> Key: HIVE-2284
> URL: https://issues.apache.org/jira/browse/HIVE-2284
> Project: Hive
> Issue Type: Improvement
> Reporter: Ning Zhang
> Assignee: Ning Zhang
> Fix For: 0.8.0
>
> Attachments: HIVE-2284.patch
>
>
> Currently bucketized mapjoin only allow the join keys being exactly the same
> as bucketized columns. This is too restrictive and is missing some
> optimization opportunities.
> If tables S and T are both bucketized on column A with the same # of buckets,
> and the query is something like:
> <code>
> SELECT /*+ MAPJOIN (S) */ ...
> FROM S join T
> ON (S.A = T.A AND S.B = T.B)
> <code>
> We should allow bucketized mapjoin since it's straightforward that bucket 1
> from S join with bucket 2 from T on such join condition must be empty.
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