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From szets...@apache.org
Subject svn commit: r756858 - in /hadoop/core/trunk: CHANGES.txt src/mapred/mapred-default.xml
Date Sat, 21 Mar 2009 01:15:49 GMT
Author: szetszwo
Date: Sat Mar 21 01:15:48 2009
New Revision: 756858

URL: http://svn.apache.org/viewvc?rev=756858&view=rev
Log:
HADOOP-5519. Remove claims from mapred-default.xml that prime numbers of tasks are helpful.
 (Owen O'Malley via szetszwo)

Modified:
    hadoop/core/trunk/CHANGES.txt
    hadoop/core/trunk/src/mapred/mapred-default.xml

Modified: hadoop/core/trunk/CHANGES.txt
URL: http://svn.apache.org/viewvc/hadoop/core/trunk/CHANGES.txt?rev=756858&r1=756857&r2=756858&view=diff
==============================================================================
--- hadoop/core/trunk/CHANGES.txt (original)
+++ hadoop/core/trunk/CHANGES.txt Sat Mar 21 01:15:48 2009
@@ -1077,6 +1077,9 @@
     HADOOP-5520. Fix a typo in disk quota help message.  (Ravi Phulari
     via szetszwo)
 
+    HADOOP-5519. Remove claims from mapred-default.xml that prime numbers
+    of tasks are helpful.  (Owen O'Malley via szetszwo)
+
 Release 0.19.2 - Unreleased
 
   BUG FIXES

Modified: hadoop/core/trunk/src/mapred/mapred-default.xml
URL: http://svn.apache.org/viewvc/hadoop/core/trunk/src/mapred/mapred-default.xml?rev=756858&r1=756857&r2=756858&view=diff
==============================================================================
--- hadoop/core/trunk/src/mapred/mapred-default.xml (original)
+++ hadoop/core/trunk/src/mapred/mapred-default.xml Sat Mar 21 01:15:48 2009
@@ -322,8 +322,7 @@
 <property>
   <name>mapred.map.tasks</name>
   <value>2</value>
-  <description>The default number of map tasks per job.  Typically set
-  to a prime several times greater than number of available hosts.
+  <description>The default number of map tasks per job.
   Ignored when mapred.job.tracker is "local".  
   </description>
 </property>
@@ -331,9 +330,10 @@
 <property>
   <name>mapred.reduce.tasks</name>
   <value>1</value>
-  <description>The default number of reduce tasks per job.  Typically set
-  to a prime close to the number of available hosts.  Ignored when
-  mapred.job.tracker is "local".
+  <description>The default number of reduce tasks per job. Typically set to 99%
+  of the cluster's reduce capacity, so that if a node fails the reduces can 
+  still be executed in a single wave.
+  Ignored when mapred.job.tracker is "local".
   </description>
 </property>
 



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