[ https://issues.apache.org/jira/browse/MAPREDUCE-4815?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14329688#comment-14329688 ]
Xuan Gong commented on MAPREDUCE-4815: -------------------------------------- [~l201514] Thanks for the patch. Could we put the configuration "FILEOUTPUTCOMMITTER_ALGORITHM_VERSION" into MRJobConfig ? We could use something like: MRJobConfig.fileoutputcommitter_algorithem_version instead of org.apache.hadoop.mapreduce.lib.output.FileOutputCommitter.FILEOUTPUTCOMMITTER_ALGORITHM_VERSION ? Also, could we add more documentation on this configuration to tell users what changes we have made between version 1 and version 2 ? > FileOutputCommitter.commitJob can be very slow for jobs with many output files > ------------------------------------------------------------------------------ > > Key: MAPREDUCE-4815 > URL: https://issues.apache.org/jira/browse/MAPREDUCE-4815 > Project: Hadoop Map/Reduce > Issue Type: Bug > Components: mrv2 > Affects Versions: 0.23.3, 2.0.1-alpha, 2.4.1 > Reporter: Jason Lowe > Assignee: Siqi Li > Attachments: MAPREDUCE-4815.v10.patch, MAPREDUCE-4815.v11.patch, > MAPREDUCE-4815.v12.patch, MAPREDUCE-4815.v3.patch, MAPREDUCE-4815.v4.patch, > MAPREDUCE-4815.v5.patch, MAPREDUCE-4815.v6.patch, MAPREDUCE-4815.v7.patch, > MAPREDUCE-4815.v8.patch, MAPREDUCE-4815.v9.patch > > > If a job generates many files to commit then the commitJob method call at the > end of the job can take minutes. This is a performance regression from 1.x, > as 1.x had the tasks commit directly to the final output directory as they > were completing and commitJob had very little to do. The commit work was > processed in parallel and overlapped the processing of outstanding tasks. In > 0.23/2.x, the commit is single-threaded and waits until all tasks have > completed before commencing. -- This message was sent by Atlassian JIRA (v6.3.4#6332)