[jira] [Created] (ARROW-12044) [C++][Compute] Add support for imperfect grouping for use in radix partitioning

["Ben Kietzman (Jira)" <ji...@apache.org>]

Ben Kietzman created ARROW-12044:
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             Summary: [C++][Compute] Add support for imperfect grouping for use in radix partitioning
                 Key: ARROW-12044
                 URL: https://issues.apache.org/jira/browse/ARROW-12044
             Project: Apache Arrow
          Issue Type: Improvement
          Components: C++
            Reporter: Ben Kietzman


ARROW-11591 adds Grouper for identifying groups based on multiple key columns.

For a large number of groups, it is beneficial to do a first pass partitioning on the key columns so that each worker thread only handles a subset of the query's groups. This is usually accomplished by computing only the hashes of the keys (not full group identity) and pushing slices of the input batches to workers based on those.

This would probably make sense as a member function of Grouper, maybe Grouper::ConsumeImperfect



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