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  1. Hadoop Map/Reduce
  2. MAPREDUCE-6795

Update the document for JobConf#setNumReduceTasks

    Details

    • Type: Improvement
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 2.8.0, 3.0.0-alpha2
    • Component/s: documentation
    • Labels:
      None
    • Hadoop Flags:
      Reviewed

      Description

      The following document is for MRv1. We should update the document for MapReduce on YARN.

      JobConf.java
         * <b id="NoOfReduces">How many reduces?</b>
         * 
         * <p>The right number of reduces seems to be <code>0.95</code> or 
         * <code>1.75</code> multiplied by (&lt;<i>no. of nodes</i>&gt; * 
         * <a href="{@docRoot}/../mapred-default.html#mapreduce.tasktracker.reduce.tasks.maximum">
         * mapreduce.tasktracker.reduce.tasks.maximum</a>).
         * </p>
      

        Attachments

        1. MAPREDUCE-6795.002.patch
          2 kB
          Yiqun Lin
        2. MAPREDUCE-6795.001.patch
          1 kB
          Yiqun Lin

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              • Assignee:
                linyiqun Yiqun Lin
                Reporter:
                ajisakaa Akira Ajisaka
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                • Created:
                  Updated:
                  Resolved: