[IMPALA-6429] Decimal division returns an incorrect result

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: Impala 2.11.0
• Fix Version/s: Impala 3.0
• Component/s: Backend
• Labels: broken-build
• Epic Color: ghx-label-5
• Assignee: Taras Bobrovytsky
• Reporter: Taras Bobrovytsky
• Created: 19/Jan/18 23:17
• Updated: 02/Feb/18 01:17
• Resolved: 02/Feb/18 01:17

Description

This bug was found by the decimal fuzzer in one of our exhaustive nigthly builds.

Query:

select cast(9269574547799442144750864826042582 as decimal(38,2)) / cast(-0.2475880078570760549798248447 as decimal(38,38))

Result:

-25071524537367060442348433289920.875272

The expected results should be around:

-37439513440208481766456680165938338.924

I computed the expected result in Python. Even without a calculator, it should be obvious that the first digit of the expected result should be higher than 2.