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HBase, mail # user - MapReduce: Reducers partitions.


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Jean-Marc Spaggiari 2013-04-10, 12:49
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Nitin Pawar 2013-04-10, 12:55
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Jean-Marc Spaggiari 2013-04-10, 13:54
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Ted Yu 2013-04-10, 13:58
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Nitin Pawar 2013-04-10, 14:01
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Jean-Marc Spaggiari 2013-04-10, 14:03
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Jean-Marc Spaggiari 2013-04-10, 18:26
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Graeme Wallace 2013-04-10, 18:52
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Jean-Marc Spaggiari 2013-04-10, 19:01
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Stack 2013-04-11, 00:33
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Jean-Marc Spaggiari 2013-04-11, 11:52
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Ted Yu 2013-04-11, 00:03
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Graeme Wallace 2013-04-10, 19:06
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Re: MapReduce: Reducers partitions.
Stack 2013-04-11, 00:26
On Wed, Apr 10, 2013 at 6:54 AM, Jean-Marc Spaggiari <
[EMAIL PROTECTED]> wrote:

> Hi Nitin,
>
> You got my question correctly.
>
> However, I'm wondering how it's working when it's done into HBase.

We use the default MapReduce partitioner:
http://hadoop.apache.org/docs/r2.0.3-alpha/api/org/apache/hadoop/mapreduce/lib/partition/HashPartitioner.html

> Do we have defaults partionners ...

No.

> ...so we have the same garantee that records
> mapping to one key go to the same reducer.

This will happen w/ the default partitioner (key is hashed.  hash is always
the same so always goes to same location).

> Or do we have to implement
> this one our own.
>

No.

St.Ack