[HIVE-5872] Make UDAFs such as GenericUDAFSum report accurate precision/scale for decimal types

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.12.0
• Fix Version/s: 0.13.0
• Component/s: Types, UDF
• Assignee: Xuefu Zhang
• Reporter: Xuefu Zhang
• Created: 22/Nov/13 14:51
• Updated: 28/Jul/14 14:04
• Resolved: 09/Dec/13 21:10

Description

Currently UDAFs are still reporting system default precision/scale (38, 18) for decimal results. Not only this is coarse, but also this can cause problems in subsequent operators such as division, where the result is dependent on the precision/scale of the input, which can go out of bound (38,38). Thus, these UDAFs should correctly report the precision/scale of the result.

Issue Links

• depends upon: HIVE-5866 Hive divide operator generates wrong results in certain cases
• is part of: HIVE-3976 Support specifying scale and precision with Hive decimal type
• is related to: HIVE-6459 Change the precison/scale for intermediate sum result in the avg() udf
• links to: https://reviews.apache.org/r/16008/