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https://issues.apache.org/jira/browse/HIVE-3430?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13448814#comment-13448814
]
Yin Huai commented on HIVE-3430:
--------------------------------
Yes, YSmart (https://issues.apache.org/jira/browse/HIVE-2206) can optimize this
pattern.
For the query shown below, two jobs will be generated. The first one takes care
the join operation on "key", and the second one takes care group by and join
operations on "value".
{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}
> group by followed by join with the same key should be optimized
> ---------------------------------------------------------------
>
> Key: HIVE-3430
> URL: https://issues.apache.org/jira/browse/HIVE-3430
> Project: Hive
> Issue Type: Improvement
> Components: Query Processor
> Reporter: Namit Jain
>
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