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https://issues.apache.org/jira/browse/MAPREDUCE-3310?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13872903#comment-13872903
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Alejandro Abdelnur commented on MAPREDUCE-3310:
-----------------------------------------------
Arggh,
{code}
@InterfaceAudience.Public
@InterfaceStability.Evolving
public interface JobContext extends MRJobConfig {
...
}
{code}
No mention about 'public-evolving' in the compatibility guide
(http://hadoop.apache.org/docs/current/hadoop-project-dist/hadoop-common/Compatibility.html#Compatibility_types).
Now going to this particular change, it will not affect user MR applications as
the JobContext is provided by the framework.
Tez could address this compilation issue by implementing the the new method
throwing an {{UnsupportedException}} and then on timely manner replace it with
a functioning implementation.
[~jeagles], Would this work?
Also we should update the compatibility guide to explicitly cover
'public-evolving' APIs.
> 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
> Fix For: 1.3.0, 2.4.0
>
> Attachments: MAPREDUCE-3310-branch-1.patch,
> MAPREDUCE-3310-branch-1.patch, MAPREDUCE-3310-trunk.patch,
> MAPREDUCE-3310-trunk.patch, MAPREDUCE-3310-trunk.patch,
> 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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