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https://issues.apache.org/jira/browse/HIVE-3763?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13527720#comment-13527720
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Namit Jain commented on HIVE-3763:
----------------------------------
This is independent of HIVE-3633.
Even a simple query like:
SELECT /*+mapjoin(b)*/ count(*) FROM test_table1 a JOIN test_table2 b ON a.key
= b.key;
requires 2 MR jobs, if test_table1 and test_table2 are sorted and bucketed by
key
> 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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