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From "Rahul Challapalli (JIRA)" <j...@apache.org>
Subject [jira] [Created] (DRILL-2046) Merge join inconsistent results
Date Tue, 20 Jan 2015 19:45:34 GMT
Rahul Challapalli created DRILL-2046:
----------------------------------------

             Summary: Merge join inconsistent results
                 Key: DRILL-2046
                 URL: https://issues.apache.org/jira/browse/DRILL-2046
             Project: Apache Drill
          Issue Type: Bug
          Components: Execution - Operators
            Reporter: Rahul Challapalli
            Assignee: Aman Sinha
            Priority: Critical


git.commit.id.abbrev=a418af1

The below queries should result in the same no of records. However the counts do not match
when we use merge join.

{code}
alter session set `planner.enable_hashjoin` = false;

select ws1.* from widestrings_small ws1 INNER JOIN widestrings_small ws2 on ws1.str_fixed_null_empty=ws2.str_var_null_empty
where ws1.str_fixed_null_empty is not null and ws2.str_var_null_empty is not null and ws1.tinyint_var
> 120;

6 records

select count(*) from widestrings_small ws1 INNER JOIN widestrings_small ws2 on ws1.str_fixed_null_empty=ws2.str_var_null_empty
where ws1.str_fixed_null_empty is not null and ws2.str_var_null_empty is not null and ws1.tinyint_var
> 120;

60 records

select count(ws1.str_var) from widestrings_small ws1 INNER JOIN widestrings_small ws2 on ws1.str_fixed_null_empty=ws2.str_var_null_empty
where ws1.str_fixed_null_empty is not null and ws2.str_var_null_empty is not null and ws1.tinyint_var
> 120;

4 records

{code}

For hash join all the above queries result in 60 records. I attached the dataset used. Let
me know if you have any questions.




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