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From "dima machlin (JIRA)" <j...@apache.org>
Subject [jira] [Created] (HIVE-5964) Hive missing a filter predicate causing wrong results joining tables after sort by
Date Thu, 05 Dec 2013 13:33:35 GMT
dima machlin created HIVE-5964:
----------------------------------

             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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