[HIVE-22233] Wrong result with vectorized execution when column value is casted to TINYINT

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.3.4, 2.3.6, 3.1.1
• Component/s: Vectorization
• Assignee: wenjun ma
• Reporter: Ganesha Shreedhara
• Created: 24/Sep/19 05:31
• Updated: 24/Feb/21 13:52

Description

Casting a column value to TINYINT is giving incorrect result when vectorized mode of the reduce-side GROUP BY query execution is enabled by setting hive.vectorized.execution.reduce.groupby.enabled parameter (enabled by default). This issue is only when the sub query has SUM/COUNT aggregation operations in IF condition.  

 

Steps to reproduce: 

create table test(id int);
insert into test values (1);
SELECT CAST(col AS TINYINT) col_cast FROM ( SELECT IF(SUM(1) > 0, 1, 0) col FROM test) x;

 

Result:

0

Expected result:

1

 

We get the expected result when hive.vectorized.execution.reduce.groupby.enabled parameter is disabled. 

We also get the expected result when we don't CAST or don't have SUM/COUNT aggregation in IF condition.

The following queries give correct result when hive.vectorized.execution.reduce.groupby.enabled is set.  

SELECT CAST(col AS INT) col_cast FROM ( SELECT IF(SUM(1) > 0, 1, 0) col FROM test) x;
SELECT col FROM ( SELECT IF(SUM(1) > 0, 1, 0) col FROM test) x;
SELECT CAST(col AS TINYINT) col_cast FROM ( SELECT IF(2 > 1, 1, 0) col FROM test) x;
SELECT CAST(col AS TINYINT) col_cast FROM ( SELECT IF(true, 1, 0) col FROM test) x;

 

This issue is only when we use CAST(col AS TINYINT) along with IF(SUM(1) > 0, 1, 0) or IF(COUNT(1) > 0, 1, 0) in sub query.