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From "Owen O'Malley" <omal...@apache.org>
Subject Re: Hadoop and Hibernate
Date Tue, 28 Feb 2012 18:17:42 GMT
On Tue, Feb 28, 2012 at 5:15 PM, Geoffry Roberts
<geoffry.roberts@gmail.com> wrote:

> If I create an executable jar file that contains all dependencies required
> by the MR job do all said dependencies get distributed to all nodes?

You can make a single jar and that will be distributed to all of the
machines that run the task, but it is better in most cases to use the
distributed cache.

See http://hadoop.apache.org/common/docs/r1.0.0/mapred_tutorial.html#DistributedCache

> If I specify but one reducer, which node in the cluster will the reducer
> run on?

The scheduling is done by the JobTracker and it isn't possible to
control the location of the reducers.

-- Owen

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