[IMPALA-6202] mod and % should be equivalent

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Impala 2.11.0
• Fix Version/s: Impala 3.1.0
• Epic Color: ghx-label-7
• Assignee: Yongjun Zhang
• Reporter: Jim Apple
• Created: 16/Nov/17 18:01
• Updated: 02/Oct/18 22:48
• Resolved: 02/Oct/18 22:48

Description

The docs say:

"mod(numeric_type a, same_type b) Purpose: Returns the modulus of a number. Equivalent to the % arithmetic operator."

and

"fmod(double a, double b), fmod(float a, float b) Purpose: Returns the modulus of a floating-point number. Equivalent to the % arithmetic operator."

But these can't both be true:

[localhost:21000] > select typeof(9.9 % 3), typeof(mod(9.9, 3)), typeof(fmod(9.9, 3));
+-----------------+---------------------+----------------------+
| typeof(9.9 % 3) | typeof(mod(9.9, 3)) | typeof(fmod(9.9, 3)) |
+-----------------+---------------------+----------------------+
| DECIMAL(2,1)    | DECIMAL(4,1)        | FLOAT                |
+-----------------+---------------------+----------------------+

Issue Links

• is duplicated by: IMPALA-7160 The resulting type of decimal mod is computed incorrectly
• is related to: IMPALA-7575 Fix doc for fmod, mod and %