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Hudson commented on MAPREDUCE-4228: ----------------------------------- Integrated in Hadoop-Hdfs-trunk #1089 (See [https://builds.apache.org/job/Hadoop-Hdfs-trunk/1089/]) MAPREDUCE-4228. mapreduce.job.reduce.slowstart.completedmaps is not working properly (Jason Lowe via bobby) (Revision 1354181) Result = FAILURE bobby : http://svn.apache.org/viewcvs.cgi/?root=Apache-SVN&view=rev&rev=1354181 Files : * /hadoop/common/trunk/hadoop-mapreduce-project/CHANGES.txt * /hadoop/common/trunk/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapreduce/v2/app/rm/RMContainerAllocator.java * /hadoop/common/trunk/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/test/java/org/apache/hadoop/mapreduce/v2/app/TestRMContainerAllocator.java > mapreduce.job.reduce.slowstart.completedmaps is not working properly to delay > the scheduling of the reduce tasks > ---------------------------------------------------------------------------------------------------------------- > > Key: MAPREDUCE-4228 > URL: https://issues.apache.org/jira/browse/MAPREDUCE-4228 > Project: Hadoop Map/Reduce > Issue Type: Bug > Components: applicationmaster, mrv2 > Affects Versions: 0.23.1 > Reporter: Jason Lowe > Assignee: Jason Lowe > Fix For: 0.23.3, 2.0.1-alpha, 3.0.0 > > Attachments: MAPREDUCE-4228.patch, MAPREDUCE-4228.patch, > MAPREDUCE-4228.patch > > > If no more map tasks need to be scheduled but not all have completed, the > ApplicationMaster will start scheduling reducers even if the number of > completed maps has not met the mapreduce.job.reduce.slowstart.completedmaps > threshold. For example, if the property is set to 1.0 all maps should > complete before any reducers are scheduled. However the reducers are > scheduled as soon as the last map task is assigned to a container. For a job > with very long-running maps, a cluster with enough capacity to launch all map > tasks could cause reducers to launch prematurely and waste cluster resources. > Thanks to Phil Su for discovering this issue. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira