[GitHub] [arrow-rs] askoa opened a new issue, #3701: `take_run` improvements

["askoa (via GitHub)" <gi...@apache.org>]

askoa opened a new issue, #3701:
URL: https://github.com/apache/arrow-rs/issues/3701

   **Is your feature request related to a problem or challenge? Please describe what you are trying to do.**
   The current implementation of `take_run` only handles `PrimitiveArray`.  Also, it's slow as it compares the values. Extending the current approach to String and Binary values will make the solution much slower.
   
   **Describe the solution you'd like**
   Instead of run encoding taken values, we can run encode taken physical indices. This will be significantly faster for String and Binary values as we will avoid comparing values. The drawback of this approach is that in certain scenarios the output might not be efficiently run encoded. For e.g. given a `RunArray { run_ends=[2,4,6,8], values=[1,2,1,2] }` and take indices `[2,3,6,7]`, the output will be `RunArray { run_ends=[2,4], values=[2,2] }` rather than `RunArray { run_ends=[4], values=[2] }`
   
   **Describe alternatives you've considered**
   We continue with the current approach of comparing values which, in creation scenarios, will result in efficient run encoded array at the cost of performance.
   
   **Additional context**
   https://github.com/apache/arrow-rs/pull/3622#discussion_r1089826535


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[GitHub] [arrow-rs] tustvold commented on issue #3701: `take_run` improvements

["tustvold (via GitHub)" <gi...@apache.org>]

tustvold commented on issue #3701:
URL: https://github.com/apache/arrow-rs/issues/3701#issuecomment-1443405170

   `label_issue.py` automatically added labels {'arrow'} from #3705


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[GitHub] [arrow-rs] tustvold closed issue #3701: `take_run` improvements

["tustvold (via GitHub)" <gi...@apache.org>]

tustvold closed issue #3701: `take_run` improvements
URL: https://github.com/apache/arrow-rs/issues/3701


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