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Date: Tue, 11 Aug 2009 16:59:24 -0700
From: Jakob Homan <jhoman@yahoo-inc.com>
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To: common-user@hadoop.apache.org
Subject: Re: Creating a job
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Hey Mithila-
    I would point you to the WordCount example 
(http://hadoop.apache.org/common/docs/current/mapred_tutorial.html) for 
a basic example of how jobs are created by supplying a JobConf to the 
JobClient.  This will submit your conf to the cluster which will create 
and run the job.

The JobControl class is to manager a series of jobs that are dependent 
on each other. Is this a situation you're facing? If not, the job 
submission strategy in the WordCount example should be sufficient.

Regarding threading: Writing multi-thread apps is generally not needed, 
as Hadoop provides parallelization via MapReduce.  However, there is a 
MultithreadedMapper for situations where you may not be maxing out the 
CPU in a specific Mapper.

It sounds like it may be helpful to check out the job submission 
documentation: 
http://hadoop.apache.org/common/docs/current/mapred_tutorial.html#Job+Submission+and+Monitoring 
  Let us know if anything is unclear after that.

Thanks,

Jakob Homan
Yahoo!

Mithila Nagendra wrote:
> Hello All
> 
> How do I create a Job in Hadoop using Class Job? And how do I run it?
> Generally JobClient.runJob(conf) is used, but the parameter in not of the
> type Job.
> 
> Also How do I use the class JobControl? Can I create Threads in a Hadoop
> (similar to multithreading in JAVA), where different Threads call diffrent
> hadoop jobs? I guess JobControl is connected to all this in some way.
> 
> Thanks for you help
> Mithila Nagendra
>