[ARROW-9756] [Rust] [DataFusion] Add support for generic return types of scalar UDFs

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Invalid
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/25808
• Assignee: Jorge Leitão
• Reporter: Jorge Leitão
• Created: 16/Aug/20 10:34
• Updated: 11/Jan/23 08:08
• Resolved: 23/Jul/21 14:43

Description

Currently, we have math functions declared as UDFs that while they can be evaluated against float32 and float64, their return type is fixed (float64).

This issue is about extending the UDF interface to support generic return types (a function), so that developers (us included), can register UDFs or variable return types.

There is a small overhead in this, since evaluating types now requires a function call, however, IMO this is still very small when compared to anything, as we are talking about plans. We can always apply some caching if needed.

Issue Links

• links to: GitHub Pull Request #7974