Joins involving where statements with a partition do not prune correctly in
left outer join
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Key: HIVE-2677
URL: https://issues.apache.org/jira/browse/HIVE-2677
Project: Hive
Issue Type: Bug
Affects Versions: 0.7.0
Reporter: Jakob Homan
The following query:
{noformat}
select t1.id as m_id, count(t2.id) as totals
from table1 t1 left outer join table2 t2 on (t1.id = t2.id)
where (datepartition == '2011-11-08-00')
group by t1.id;{noformat}
should prune to just a single partition (datepartition == '2011-11-08-00') .
However, the filter is being applied in the reducer, so a full table scan is
being done as part of the map.
One can get the correct behavior by pushing the filter into a select statement
within the join itself:
{noformat}select t1.id as m_id, count(p.id) as totals
from table1 t1 left outer join (select * from table2 where datepartition ==
'2011-11-08-00') t2 on (t1.id = t2.id)
group by t1.id;{noformat}
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