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Posted to dev@arrow.apache.org by "Liya Fan (Jira)" <ji...@apache.org> on 2019/10/17 04:16:00 UTC

[jira] [Created] (ARROW-6911) [Java] Provide composite comparator

Liya Fan created ARROW-6911:
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             Summary: [Java] Provide composite comparator
                 Key: ARROW-6911
                 URL: https://issues.apache.org/jira/browse/ARROW-6911
             Project: Apache Arrow
          Issue Type: New Feature
          Components: Java
            Reporter: Liya Fan
            Assignee: Liya Fan


A composite comparator is a sub-class of VectorValueComparator that contains an array of inner comparators, with each comparator corresponding to one column for comparison. It can be used to support sort/comparison operations for VectorSchemaRoot/StructVector.

The composite comparator works like this: it first uses the first internal comparator (for the primary sort key) to compare vector values. If it gets a non-zero value, we just return it; otherwise, we use the second comparator to break the tie, and so on, until a non-zero value is produced by some internal comparator, or all internal comparators have been used. 




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