[DRILL-2207] Fix Union All Operator

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Fix Version/s: 0.8.0
• Component/s: Execution - Relational Operators
• Assignee: Sean Hsuan-Yi Chu
• Reporter: Sean Hsuan-Yi Chu
• Created: 11/Feb/15 01:06
• Updated: 15/Mar/15 19:53
• Resolved: 10/Mar/15 16:59

Description

The current specification/behavior of UNION ALL is not well defined.
This issue attempts to reach agreement on the expected behavior of UNION ALL.

A link for the latest design document is below:
https://docs.google.com/document/d/1OQFQ6IvdeBJkDLKHFBlwP3tle2WuzpBgZf6R_6Vh0mw/edit
..............................................................................................................................

An example of the current implementation:
(select n_name from cp.`tpch/nation.parquet` limit 1)" +
"UNION ALL " +
"(select r_name from cp.`tpch/region.parquet` limit 1);

returns:

n_name
ALGERIA
r_name
AFRICA

Issue Links

• is depended upon by: DRILL-1847 Union All does not match corresponding columns by index to union columns
• is depended upon by: DRILL-1886 NPE in queries with a project on a subquery with Union all
• is depended upon by: DRILL-1923 Unexpected exception when one column of a leg of a UNION ALL is a numeric constant
• is depended upon by: DRILL-1977 Wrong result with aggregation on top of UNION ALL operator
• is depended upon by: DRILL-2203 DISTINCT over UNION ALL subquery with fully qualified column names returns wrong result
• is depended upon by: DRILL-2204 DISTINCT statement over UNION ALL subquery asserts during execution with streaming aggregation
• is depended upon by: DRILL-2317 UNION ALL on sub-queries with single column projection fails on GROUP BY
• is depended upon by: DRILL-2376 UNION ALL on Aggregates with GROUP BY returns incomplete results
• is depended upon by: DRILL-2377 UNION ALL on Aggregates with GROUP BY returns null when column aliases don't match
• is depended upon by: DRILL-2378 UNION ALL on Aggregates with GROUP BY and ORDER BY fails when column aliases don't match
• is depended upon by: DRILL-2379 UNION ALL with ORDER BY fails when column aliases don't match