[DRILL-6070] Hash join with empty tables should not do casting of data types to INT<OPTIONAL>

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Resolved
• Fix Version/s: 1.13.0
• Assignee: Vitalii Diravka
• Reporter: Vitalii Diravka
• Created: 04/Jan/18 16:27
• Updated: 06/Feb/18 19:15
• Resolved: 06/Feb/18 19:15

Description

LeftJoin query by leveraging HashJoin operator leads to error, but by using MergeJoin works fine.

0: jdbc:drill:zk=local> alter session set `planner.enable_hashjoin` = true;
+-------+-----------------------------------+
|  ok   |              summary              |
+-------+-----------------------------------+
| true  | planner.enable_hashjoin updated.  |
+-------+-----------------------------------+
1 row selected (0.078 seconds)
0: jdbc:drill:zk=local> alter session set `planner.enable_mergejoin` = false;
+-------+------------------------------------+
|  ok   |              summary               |
+-------+------------------------------------+
| true  | planner.enable_mergejoin updated.  |
+-------+------------------------------------+
1 row selected (0.079 seconds)
0: jdbc:drill:zk=local> select t1.a1, t1.b1, t2.a2, t2.b2 from dfs.`/tmp/nullable1.json` t1 left join dfs.`/tmp/empty0.json` t2 on t1.b1 = t2.b2;
Error: SYSTEM ERROR: DrillRuntimeException: Join only supports implicit casts between 1. Numeric data
 2. Varchar, Varbinary data 3. Date, Timestamp data Left type: VARCHAR, Right type: INT. Add explicit casts to avoid this error

Fragment 0:0

[Error Id: 2cfc662f-48c2-4e62-a2ea-5a0f33d64c9b on vitalii-pc:31010] (state=,code=0)

00-00    Screen : rowType = RecordType(ANY a1, ANY b1, ANY a2, ANY b2): rowcount = 1.0, cumulative cost = {2.1 rows, 20.1 cpu, 0.0 io, 0.0 network, 17.6 memory}, id = 930
00-01      Project(a1=[$0], b1=[$1], a2=[$2], b2=[$3]) : rowType = RecordType(ANY a1, ANY b1, ANY a2, ANY b2): rowcount = 1.0, cumulative cost = {2.0 rows, 20.0 cpu, 0.0 io, 0.0 network, 17.6 memory}, id = 929
00-02        Project(a1=[$1], b1=[$0], a2=[$3], b2=[$2]) : rowType = RecordType(ANY a1, ANY b1, ANY a2, ANY b2): rowcount = 1.0, cumulative cost = {2.0 rows, 20.0 cpu, 0.0 io, 0.0 network, 17.6 memory}, id = 928
00-03          HashJoin(condition=[=($0, $2)], joinType=[left]) : rowType = RecordType(ANY b1, ANY a1, ANY b2, ANY a2): rowcount = 1.0, cumulative cost = {2.0 rows, 20.0 cpu, 0.0 io, 0.0 network, 17.6 memory}, id = 927
00-05            Scan(groupscan=[EasyGroupScan [selectionRoot=file:/home/vitalii/IdeaProjects/drill-fork/exec/java-exec/target/test-classes/jsoninput/nullable1.json, numFiles=1, columns=[`b1`, `a1`], files=[file:/home/vitalii/IdeaProjects/drill-fork/exec/java-exec/target/test-classes/jsoninput/nullable1.json]]]) : rowType = RecordType(ANY b1, ANY a1): rowcount = 1.0, cumulative cost = {0.0 rows, 0.0 cpu, 0.0 io, 0.0 network, 0.0 memory}, id = 925
00-04            Scan(groupscan=[EasyGroupScan [selectionRoot=file:/home/vitalii/IdeaProjects/drill-fork/exec/java-exec/src/test/resources/project/pushdown/empty0.json, numFiles=1, columns=[`b2`, `a2`], files=[file:/home/vitalii/IdeaProjects/drill-fork/exec/java-exec/src/test/resources/project/pushdown/empty0.json]]]) : rowType = RecordType(ANY b2, ANY a2): rowcount = 1.0, cumulative cost = {0.0 rows, 0.0 cpu, 0.0 io, 0.0 network, 0.0 memory}, id = 926

Left join with empty tables should not do casting of data types to INT<OPTIONAL>.
The result should be the same as for MergeJoin operator:

0: jdbc:drill:zk=local> alter session set `planner.enable_hashjoin` = false;
+-------+-----------------------------------+
|  ok   |              summary              |
+-------+-----------------------------------+
| true  | planner.enable_hashjoin updated.  |
+-------+-----------------------------------+
1 row selected (0.087 seconds)
0: jdbc:drill:zk=local> alter session set `planner.enable_mergejoin` = true;
+-------+------------------------------------+
|  ok   |              summary               |
+-------+------------------------------------+
| true  | planner.enable_mergejoin updated.  |
+-------+------------------------------------+
1 row selected (0.073 seconds)
0: jdbc:drill:zk=local> select t1.a1, t1.b1, t2.a2, t2.b2 from dfs./tmp/nullable1.json` t1 left join dfs.`/tmp/empty0.json` t2 on t1.b1 = t2.b2;
+-----+-------+-------+-------+
| a1  |  b1   |  a2   |  b2   |
+-----+-------+-------+-------+
| 1   | abc   | null  | null  |
| 2   | null  | null  | null  |
+-----+-------+-------+-------+
2 rows selected (0.624 seconds)

Note: nullable1.json is in attachments and empty0.json is an empty file

Issue Links

• relates to: DRILL-5851 Empty table during a join operation with a non empty table produces cast exception
• relates to: DRILL-4185 UNION ALL involving empty directory on any side of union all results in Failed query