[GitHub] [arrow] vertexclique commented on pull request #8630: ARROW-10540 [Rust] Improve filtering

[GitBox <gi...@apache.org>]

vertexclique commented on pull request #8630:
URL: https://github.com/apache/arrow/pull/8630#issuecomment-725436304


   ```
   Naming: I have seen similar concepts called "Masks" (as they are similar to bit masks) -- so perhaps ArrayDataMask or MaskedArrayData. Or perhaps ArrayRowSet
   
   When I actually read the code about MutableArrayData I realize that it isn't quite the mask concept, but it is similar (intermediate results want to represent "what indexes pass a certain test" and then eventually copying only those indexes to a new array"
   
   This type of structure might also useful for performing multiple boolean operations (eg. when doing (A > 5) AND A < 10 you can compute the row ids/indexes for that pass A > 5 and then rather than actually copying those rows to then compare them less than B you can operate directly on the original copy of A (check only the rows where the mask is true)
   ```
   I found the whole block of this comment true. There are other approaches to do this but the main approach is that. I believe scratchpad implementation can also solve this problem from the different looking glass.


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