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Posted to mapreduce-issues@hadoop.apache.org by "Hadoop QA (JIRA)" <ji...@apache.org> on 2013/11/15 03:57:22 UTC
[jira] [Commented] (MAPREDUCE-3310) Custom grouping comparator
cannot be set for Combiners
[ https://issues.apache.org/jira/browse/MAPREDUCE-3310?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13823238#comment-13823238 ]
Hadoop QA commented on MAPREDUCE-3310:
--------------------------------------
{color:red}-1 overall{color}. Here are the results of testing the latest attachment
http://issues.apache.org/jira/secure/attachment/12613990/MAPREDUCE-3310-trunk.patch
against trunk revision .
{color:green}+1 @author{color}. The patch does not contain any @author tags.
{color:green}+1 tests included{color}. The patch appears to include 2 new or modified test files.
{color:red}-1 javac{color}. The applied patch generated 1546 javac compiler warnings (more than the trunk's current 1545 warnings).
{color:green}+1 javadoc{color}. The javadoc tool did not generate any warning messages.
{color:green}+1 eclipse:eclipse{color}. The patch built with eclipse:eclipse.
{color:green}+1 findbugs{color}. The patch does not introduce any new Findbugs (version 1.3.9) warnings.
{color:green}+1 release audit{color}. The applied patch does not increase the total number of release audit warnings.
{color:red}-1 core tests{color}. The patch failed these unit tests in hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient:
org.apache.hadoop.mapred.TestJobCleanup
{color:green}+1 contrib tests{color}. The patch passed contrib unit tests.
Test results: https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/4200//testReport/
Javac warnings: https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/4200//artifact/trunk/patchprocess/diffJavacWarnings.txt
Console output: https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/4200//console
This message is automatically generated.
> Custom grouping comparator cannot be set for Combiners
> ------------------------------------------------------
>
> Key: MAPREDUCE-3310
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-3310
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Components: client
> Affects Versions: 0.20.1
> Environment: All
> Reporter: Mathias Herberts
> Assignee: Alejandro Abdelnur
> Attachments: MAPREDUCE-3310-trunk.patch
>
>
> Combiners are often described as 'Reducers running on the Map side'.
> As Reducers, Combiners are fed <K,{V}>, where {V} is built by grouping values associated with the 'same' key.
> For Reducers, the comparator used for grouping values can be set independently of that used to sort the keys (using Job.setGroupingComparatorClass).
> Such a configuration is not possible for Combiners, meaning some things done in Reducers cannot be done in Combiners (such as secondary sort).
> It would be handy to have a Job.setCombinerGroupingComparatorClass method that would allow the setting of the grouping comparator used when applying a Combiner.
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