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Posted to dev@hive.apache.org by "dima machlin (JIRA)" <ji...@apache.org> on 2013/12/05 14:33:35 UTC
[jira] [Created] (HIVE-5964) Hive missing a filter predicate
causing wrong results joining tables after sort by
dima machlin created HIVE-5964:
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Summary: Hive missing a filter predicate causing wrong results joining tables after sort by
Key: HIVE-5964
URL: https://issues.apache.org/jira/browse/HIVE-5964
Project: Hive
Issue Type: Bug
Components: Query Processor
Affects Versions: 0.11.0, 0.10.0
Reporter: dima machlin
It seems like the optimization of predicate pushdown is failing under certain conditions causing wrong results as a filter predicate appears to be completely disregarded by the query processor for some reason.
Here is the scenario (assuming "dual" table exists) :
set hive.optimize.ppd=true;
drop table if exists test_tbl ;
create table test_tbl (id string,name string);
insert into table test_tbl
select 'a','b' from dual;
test_tbl now contains :
a b
the following query :
select t2.*
from
(select id,name from (select id,name from test_tbl) t1 sort by id) t2
join test_tbl t3 on (t2.id=t3.id )
where t2.name='c' and t3.id='a';
returns :
a b
The filter :" t2.name='c' " is missing from the execution plan and obviously doesn't apply.
The filter "t3.id='a' " does appear in the plan and is being applied before the join.
If the query changes a little bit like removing the sort by, removing the t1 sub-query or disabling hive.optimize.ppd then the predicate appears.
I'm able to reproduce the problem both in Hive 0.10 and Hive 0.11 although It seems to work fine in Hive 0.7
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