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Posted to dev@hive.apache.org by "Chao (JIRA)" <ji...@apache.org> on 2014/12/08 20:51:13 UTC
[jira] [Created] (HIVE-9041) Generate better plan for queries
containing both union and multi-insert [Spark Branch]
Chao created HIVE-9041:
--------------------------
Summary: Generate better plan for queries containing both union and multi-insert [Spark Branch]
Key: HIVE-9041
URL: https://issues.apache.org/jira/browse/HIVE-9041
Project: Hive
Issue Type: Bug
Components: Spark
Affects Versions: spark-branch
Reporter: Chao
This is a follow-up for HIVE-8920. For queries like:
{code}
from (select * from table0 union all select * from table1) s
insert overwrite table table3 select s.x, count(1) group by s.x
insert overwrite table table4 select s.y, count(1) group by s.y;
{code}
Currently we generate the following plan:
{noformat}
M1 M2
\ / \
U3 R5
|
R4
{noformat}
It's better, however, to have the following plan:
{noformat}
M1 M2
|\ /|
| \/ |
| /\ |
R1 R2
{noformat}
Also, we can do some reseach in this JIRA to see if it's possible
to remove UnionWork once and for all.
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