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https://issues.apache.org/jira/browse/HIVE-3669?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Yin Huai updated HIVE-3669:
---------------------------
Assignee: Yin Huai
> Support queries in which input tables of correlated MR jobs involves
> intermediate tables
> ----------------------------------------------------------------------------------------
>
> Key: HIVE-3669
> URL: https://issues.apache.org/jira/browse/HIVE-3669
> Project: Hive
> Issue Type: Sub-task
> Components: Query Processor
> Reporter: Yin Huai
> Assignee: Yin Huai
>
> Correlation optimizer implemented in HIVE-2206 does not optimize correlated
> MapReduce jobs which have intermediate tables as input.
> Here is an example originally posted in HIVE-3430
> {code:sql}
> select * from
> (
> select c.value, count(1) as cnt from
> (
> select b.key, b.value from
> (
> select key, length(value) from T1 where ds = '1'
> ) a
> join
> T2 b on b.ds = '1' and a.key = b.key
> ) c
> group by c.value
> ) d
> join
> (
> select value, count(1) as cnt from T2 c where c.ds = '1' group by value
> ) e
> on d.value = e.value;
> {code}
> Since correlated MapReduce jobs (those use "value" as the portioning key)
> involves an intermediate table "c", implementation of HIVE-2206 do not
> optimize this query.
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