[jira] [Created] (PIG-4002) Disable combiner when map-side aggregation is used

["Travis Woodruff (JIRA)" <ji...@apache.org>]

Travis Woodruff created PIG-4002:
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             Summary: Disable combiner when map-side aggregation is used
                 Key: PIG-4002
                 URL: https://issues.apache.org/jira/browse/PIG-4002
             Project: Pig
          Issue Type: Improvement
    Affects Versions: 0.13.0
            Reporter: Travis Woodruff
            Assignee: Travis Woodruff
            Priority: Minor


This may be controversial, so I'd like others' opinions on this.

It is not currently possible to disable the combiner and use map-side aggregation at the same time. This is a problematic since map-side aggregation effectively combines in the mapper, so running the combiner adds expensive combiner execution (combiner requires deserialization & reserialization) for little to no value.

PIG-2829 had a patch to disable the combiner when map-side aggregation is used (along with some other changes). This was never integrated because the map-side aggregation code was redone while this was in progress.





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