[ARROW-7754] [C++] Result<T> is slow

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.17.0
• Component/s: C++
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/23992
• Assignee: Antoine Pitrou
• Reporter: Antoine Pitrou
• Created: 03/Feb/20 20:50
• Updated: 11/Jan/23 07:55
• Resolved: 12/Feb/20 16:02

Description

When converting a short performance-critical function to return a Result (instead of returning a Status and filling a out-parameter), I noticed a catastrophic performance regression (around 2x or 3x slower).

It seems the current Result implementation is very slow, for several reasons:

• it imposes "safety" features even in release mode, for example on the critical path of move operators
• the underlying mpark variant implementation is not optimized for performance-critical data structures

Issue Links

• links to: GitHub Pull Request #6356