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From Krishna Pisupat <krishna.pisu...@gmail.com>
Subject Re: set the number of reduce tasks in the wordcount by command line
Date Wed, 25 Sep 2013 22:54:04 GMT
You can invoke the setNumReduceTasks on the Job object that you use to run the MR job. 

http://hadoop.apache.org/docs/r2.0.6-alpha/api/org/apache/hadoop/mapreduce/Job.html#setNumReduceTasks(int)

Or else you can set the property mapreduce.job.reduces in mapred-site.xml


mapreduce.job.reduces	1	The default number of reduce tasks per job. Typically set to 99% of
the cluster's reduce capacity, so that if a node fails the reduces can still be executed in
a single wave. Ignored when mapreduce.jobtracker.address is "local".




On Sep 25, 2013, at 3:17 PM, xeon <xeonmailinglist@gmail.com> wrote:

> In yarn 2.0.5, where I set this?
> 
> On 09/25/2013 11:16 PM, Shahab Yunus wrote:
>> Have you tried setting mapred.reduce.tasks property?
>> 
>> Regards,
>> Shahab
>> 
>> 
>> On Wed, Sep 25, 2013 at 6:01 PM, xeon <xeonmailinglist@gmail.com> wrote:
>> is it possible to set the number of reduce tasks in the wordcount example when I
launch the job by command line?
>> 
>> Thanks
>> 
> 


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