[IMPALA-3931] Support aggregate functions with arbitrary fixed-size intermediate type

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: Impala 2.7.0
• Fix Version/s: Impala 2.10.0
• Component/s: Backend
• Target Version: Impala 2.10.0
• Assignee: Tim Armstrong
• Reporter: Tim Armstrong
• Created: 28/Jul/16 16:58
• Updated: 17/Aug/17 03:13
• Resolved: 17/Aug/17 03:13

Description

We should support fixed-size intermediate types for aggregate functions that can contain arbitrary structures. Currently these have to be allocated and stored in variable-length string values. E.g. average functions store their intermediate results in a 16-byte struct.

There is some skeleton code for a BufferVal type in the UDF tests but we don't have end-to-end support for this.

Issue Links

• is related to: IMPALA-3304 Aggregations do not always spill when exprs use large amount of memory