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Posted to dev@hive.apache.org by "Namit Jain (JIRA)" <ji...@apache.org> on 2012/12/07 18:51:21 UTC
[jira] [Assigned] (HIVE-3763) Aggregation followed by a sort-merge
join requires a new MR job
[ https://issues.apache.org/jira/browse/HIVE-3763?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Namit Jain reassigned HIVE-3763:
--------------------------------
Assignee: Namit Jain
> Aggregation followed by a sort-merge join requires a new MR job
> ---------------------------------------------------------------
>
> Key: HIVE-3763
> URL: https://issues.apache.org/jira/browse/HIVE-3763
> Project: Hive
> Issue Type: Bug
> Reporter: Namit Jain
> Assignee: Namit Jain
>
> After Hive-3633, if tbl1 and tbl2 are tables bucketiezed and sorted by key into 2 buckets, the following query:
>
>
> select count(*) from (
> select /*+mapjoin(a)*/ a.key as key, a.value as val1, b.value as val2 from tbl1 a join tbl2 b on a.key = b.key
> ) subq1;
> requires 2 MR job - the first one is a sort-merge join, and the second MR job
> performs the count(*) on the output of the sort-merge join.
> Ideally, this should be performed in a single MR job.
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