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Hadoop QA commented on MAPREDUCE-64: ------------------------------------ +1 overall. Here are the results of testing the latest attachment http://issues.apache.org/jira/secure/attachment/12434447/M64-10.patch against trunk revision 905008. +1 @author. The patch does not contain any @author tags. +1 tests included. The patch appears to include 22 new or modified tests. +1 javadoc. The javadoc tool did not generate any warning messages. +1 javac. The applied patch does not increase the total number of javac compiler warnings. +1 findbugs. The patch does not introduce any new Findbugs warnings. +1 release audit. The applied patch does not increase the total number of release audit warnings. +1 core tests. The patch passed core unit tests. +1 contrib tests. The patch passed contrib unit tests. Test results: http://hudson.zones.apache.org/hudson/job/Mapreduce-Patch-h6.grid.sp2.yahoo.net/423/testReport/ Findbugs warnings: http://hudson.zones.apache.org/hudson/job/Mapreduce-Patch-h6.grid.sp2.yahoo.net/423/artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html Checkstyle results: http://hudson.zones.apache.org/hudson/job/Mapreduce-Patch-h6.grid.sp2.yahoo.net/423/artifact/trunk/build/test/checkstyle-errors.html Console output: http://hudson.zones.apache.org/hudson/job/Mapreduce-Patch-h6.grid.sp2.yahoo.net/423/console This message is automatically generated. > Map-side sort is hampered by io.sort.record.percent > --------------------------------------------------- > > Key: MAPREDUCE-64 > URL: https://issues.apache.org/jira/browse/MAPREDUCE-64 > Project: Hadoop Map/Reduce > Issue Type: Bug > Reporter: Arun C Murthy > Assignee: Chris Douglas > Attachments: M64-0.patch, M64-0i.png, M64-1.patch, M64-10.patch, > M64-1i.png, M64-2.patch, M64-2i.png, M64-3.patch, M64-4.patch, M64-5.patch, > M64-6.patch, M64-7.patch, M64-8.patch, M64-9.patch > > > Currently io.sort.record.percent is a fairly obscure, per-job configurable, > expert-level parameter which controls how much accounting space is available > for records in the map-side sort buffer (io.sort.mb). Typically values for > io.sort.mb (100) and io.sort.record.percent (0.05) imply that we can store > ~350,000 records in the buffer before necessitating a sort/combine/spill. > However for many applications which deal with small records e.g. the > world-famous wordcount and it's family this implies we can only use 5-10% of > io.sort.mb i.e. (5-10M) before we spill inspite of having _much_ more memory > available in the sort-buffer. The word-count for e.g. results in ~12 spills > (given hdfs block size of 64M). The presence of a combiner exacerbates the > problem by piling serialization/deserialization of records too... > Sure, jobs can configure io.sort.record.percent, but it's tedious and > obscure; we really can do better by getting the framework to automagically > pick it by using all available memory (upto io.sort.mb) for either the data > or accounting. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.