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  1. Hive
  2. HIVE-949

Object deepCopy in GroupBy Operator

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Details

    • Improvement
    • Status: Closed
    • Major
    • Resolution: Fixed
    • None
    • 0.5.0
    • None
    • None
    • Reviewed

    Description

      In GroupByOperator, objects are first deep copied and then check whether or not the object is in the hash table (in hash-mode aggregation). In fact, object deep copy could be very expensive (around 5% CPU time). A simple change could be generate the object without deep copy through ObjectInspector and check its existence in the hash table. If not exists, we call deep copy.

      Attachments

        1. hive-949-2009-11-26.patch
          9 kB
          He Yongqiang

        Issue Links

          blocks

          Improvement - An improvement or enhancement to an existing feature or task. HIVE-535 Memory-efficient hash-based Aggregation

          • Major - Major loss of function.
          • Open

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            People

              he yongqiang He Yongqiang
              nzhang Ning Zhang
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              Dates

                Created:
                Updated:
                Resolved: