[DRILL-2002] Confusing "star" behavior in UNION ALL operator

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.8.0
• Fix Version/s: 0.8.0
• Component/s: Query Planning & Optimization
• Assignee: Sean Hsuan-Yi Chu
• Reporter: Victoria Markman
• Created: 13/Jan/15 21:07
• Updated: 17/Mar/15 19:13
• Resolved: 17/Mar/15 19:13

Description

t1.json

{ "a1": 1 ,    "b1" : 1}
{ "a1": 2 ,    "b1" : 1}
{ "a1": 2 ,    "b1" : 2}
{ "a1": 3 ,    "b1" : 2}
{ "a1": null , "b1" : 3}

Star in both legs of UNION ALL works:

0: jdbc:drill:schema=dfs> select * from `t1.json` union all select * from `t1.json`;
+------------+------------+
|     a1     |     b1     |
+------------+------------+
| 1          | 1          |
| 2          | 1          |
| 2          | 2          |
| 3          | 2          |
| null       | 3          |
| 1          | 1          |
| 2          | 1          |
| 2          | 2          |
| 3          | 2          |
| null       | 3          |
+------------+------------+
10 rows selected (0.126 seconds)

I expected this to work in structured, but it seems that since planner has no idea about meta data, error message seems reasonable:

0: jdbc:drill:schema=dfs> select a1, b1 from `t1.json` union all select * from `t1.json`;
Query failed: Query failed: Failure validating SQL. org.eigenbase.util.EigenbaseContextException: At line 1, column 47: Column count mismatch in UNION ALL
Error: exception while executing query: Failure while executing query. (state=,code=0)

Query below returns very confusing result. I expected it to error out like the query above:

0: jdbc:drill:schema=dfs> select a1 from `t1.json` union all select * from `t1.json`;
+------------+
|     a1     |
+------------+
| 1          |
| 2          |
| 2          |
| 3          |
| null       |
| 1          |
| 2          |
| 2          |
| 3          |
| null       |
+------------+
10 rows selected (0.111 seconds)

Issue Links

• depends upon: DRILL-2414 Union-All on SELECT * FROM schema-less data source will throw exception