[HIVE-12384] Union Operator may produce incorrect result on TEZ

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.14.0, 1.0.0, 1.0.1, 1.1.0, 1.2.1
• Fix Version/s: 2.0.0
• Component/s: Hive
• Target Version/s: 1.3.0, 2.0.0
• Assignee: Laljo John Pullokkaran
• Reporter: Laljo John Pullokkaran
• Created: 11/Nov/15 21:12
• Updated: 05/Jan/17 13:44
• Resolved: 17/Nov/15 23:08

Description

Union queries may produce incorrect result on TEZ.
TEZ removes union op, thus might loose the implicit cast in union op.

Reproduction test case:

set hive.cbo.enable=false;
set hive.execution.engine=tez;
select (x/sum(x) over())  as y from(select cast(1 as decimal(10,0))  as x from (select * from src limit 2)s1 union all select cast(1 as decimal(10,0)) x from (select * from src limit 2) s2 union all select '100000000' x from (select * from src limit 2) s3)u order by y;

select (x/sum(x) over()) as y from(select cast(1 as decimal(10,0))  as x from (select * from src limit 2)s1 union all select cast(1 as decimal(10,0)) x from (select * from src limit 2) s2 union all select cast (null as string) x from (select * from src limit 2) s3)u order by y;

Issue Links

• is related to: HIVE-12423 Remove Union Operator in Physical Compiler