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  1. Hadoop Map/Reduce
  2. MAPREDUCE-1489

DataDrivenDBInputFormat should not query the database when generating only one split

    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 0.21.0
    • Component/s: None
    • Labels:
      None
    • Hadoop Flags:
      Reviewed

      Description

      DataDrivenDBInputFormat runs a query to establish bounding values for each split it generates; but if it's going to generate only one split (mapreduce.job.maps == 1), then there's no reason to do this. This will remove overhead associated with a single-threaded import of a non-indexed table since it avoids a full table scan.

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              • Assignee:
                kimballa Aaron Kimball
                Reporter:
                kimballa Aaron Kimball
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                • Created:
                  Updated:
                  Resolved: