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From "Aman Sinha (JIRA)" <j...@apache.org>
Subject [jira] [Created] (DRILL-886) Wrong results for a query with Right Outer Join on the second (and subsequent) executions
Date Mon, 02 Jun 2014 18:32:02 GMT
Aman Sinha created DRILL-886:
--------------------------------

             Summary: Wrong results for a query with Right Outer Join on the second (and subsequent)
executions
                 Key: DRILL-886
                 URL: https://issues.apache.org/jira/browse/DRILL-886
             Project: Apache Drill
          Issue Type: Bug
            Reporter: Aman Sinha


The following query with a right outer join produces correct results on the first execution
in a session but wrong results on the second and subsequent executions.   A potential cause
for the problem can be seen from the two Explain plans:  the scan of the nation table shows
a difference in the columns being projected.  

0: jdbc:drill:zk=local> select n.n_regionkey, r.r_regionkey from cp.`tpch/region.parquet`
r right join cp.`tpch/nation.parquet` n on  n.n_regionkey = r.r_regionkey;

+-------------+-------------+
| n_regionkey | r_regionkey |
+-------------+-------------+
| 0           | 0           |
| 0           | 0           |
| 0           | 0           |
| 0           | 0           |
| 0           | 0           |
| 1           | 1           |
| 1           | 1           |
| 1           | 1           |
| 1           | 1           |
| 1           | 1           |
| 2           | 2           |
| 2           | 2           |
| 2           | 2           |
| 2           | 2           |
| 2           | 2           |
| 3           | 3           |
| 3           | 3           |
| 3           | 3           |
| 3           | 3           |
| 3           | 3           |
| 4           | 4           |
| 4           | 4           |
| 4           | 4           |
| 4           | 4           |
| 4           | 4           |
+-------------+-------------+
25 rows selected (2.207 seconds)

0: jdbc:drill:zk=local> select n.n_regionkey, r.r_regionkey from cp.`tpch/region.parquet`
r right join cp.`tpch/nation.parquet` n on  n.n_regionkey = r.r_regionkey;
+-------------+-------------+
| n_regionkey | r_regionkey |
+-------------+-------------+
| 0           | null        |
| 1           | null        |
| 1           | null        |
| 1           | null        |
| 4           | null        |
| 0           | null        |
| 3           | null        |
| 3           | null        |
| 2           | null        |
| 2           | null        |
| 4           | null        |
| 4           | null        |
| 2           | null        |
| 4           | null        |
| 0           | null        |
| 0           | null        |
| 0           | null        |
| 1           | null        |
| 2           | null        |
| 3           | null        |
| 4           | null        |
| 2           | null        |
| 3           | null        |
| 3           | null        |
| 1           | null        |
+-------------+-------------+
25 rows selected (0.514 seconds)

EXPLAIN plan for the good run: 

| 00-00    Screen
00-01      Project(n_regionkey=[$0], r_regionkey=[$1])
00-02        Project(n_regionkey=[$3], r_regionkey=[$1])
00-03          HashJoin(condition=[=($3, $1)], joinType=[right])
00-05            Scan(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath [path=/tpch/region.parquet]],
selectionRoot=/tpch/region.parquet, columns=[SchemaPath [`r_regionkey`]]]])
00-04            Project(*0=[$0], n_regionkey=[$1])
00-06              BroadcastExchange
01-01                Scan(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath [path=/tpch/nation.parquet]],
selectionRoot=/tpch/nation.parquet, columns=[SchemaPath [`n_regionkey`]]]])

Explain plan for the bad run: 

| 00-00    Screen
00-01      Project(n_regionkey=[$0], r_regionkey=[$1])
00-02        Project(n_regionkey=[$3], r_regionkey=[$1])
00-03          HashJoin(condition=[=($2, $1)], joinType=[right])
00-05            Scan(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath [path=/tpch/region.parquet]],
selectionRoot=/tpch/region.parquet, columns=[SchemaPath [`r_regionkey`]]]])
00-04            Project(*0=[$0], n_regionkey=[$1])
00-06              BroadcastExchange
01-01                Scan(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath [path=/tpch/nation.parquet]],
selectionRoot=/tpch/nation.parquet, columns=null]])



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