[HIVE-20881] Constant propagation oversimplifies projections

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.0.0-alpha-1
• Assignee: Zoltan Haindrich
• Reporter: Zoltan Haindrich
• Created: 07/Nov/18 15:59
• Updated: 17/Nov/22 08:54
• Resolved: 10/Nov/18 13:43

Description

create table cx2(bool1 boolean);
insert into cx2 values (true),(false),(null);

set hive.cbo.enable=true;
select bool1 IS TRUE OR (cast(NULL as boolean) AND bool1 IS NOT TRUE AND bool1 IS NOT FALSE) from cx2;

+--------+
|  _c0   |
+--------+
| true   |
| false  |
| NULL   |
+--------+


set hive.cbo.enable=false;
select bool1 IS TRUE OR (cast(NULL as boolean) AND bool1 IS NOT TRUE AND bool1 IS NOT FALSE) from cx2;

+-------+
|  _c0  |
+-------+
| true  |
| NULL  |
| NULL  |
+-------+

from explain it seems the expression was simplified to: (_col0 is true or null)