Yin Huai created HIVE-3669:
------------------------------
Summary: 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
Reporter: 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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