Recently sort_indices was optimized and refactored in ARROW-14165. One of those optimizations could also be applied to select_k_unstable's implementation.

Reporter: David Li / @lidavidm

Related issues:

• [C++][Compute] Implement TopK/BottomK (relates to)
• [C++] Improve table sort performance #2 (relates to)

Original Issue Attachments:

• image-2022-02-16-02-35-42-818.png

PRs and other links:

• GitHub Pull Request #12164
• GitHub Pull Request #12582

_{Note: This issue was originally created as ARROW-14183. Please see the migration documentation for further details.}