[MAPREDUCE-6795] Update the document for JobConf#setNumReduceTasks

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.8.0, 3.0.0-alpha2
• Component/s: documentation
• Hadoop Flags: Reviewed
• Assignee: Yiqun Lin
• Reporter: Akira Ajisaka
• Created: 17/Oct/16 05:11
• Updated: 02/Nov/16 12:44
• Resolved: 01/Nov/16 11:53

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>

Issue Links

• is related to: MAPREDUCE-6794 Remove unused properties from TTConfig.java