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MapReduce, mail # user - how to find top N values using map-reduce ?


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Re: how to find top N values using map-reduce ?
Harsh J 2013-02-02, 18:05
Note that a "one reducer" isn't always the solution. If you know your
key space boundaries, consider using a total-order-partition to scale
the app/job and make use of nodes on the cluster.

On Sat, Feb 2, 2013 at 10:35 AM, praveenesh kumar <[EMAIL PROTECTED]> wrote:
> I am looking for a better solution for this.
>
> 1 way to do this would be to find top N values from each mappers and
> then find out the top N out of them in 1 reducer.  I am afraid that
> this won't work effectively if my N is larger than number of values in
> my inputsplit (or mapper input).
>
> Otherway is to just sort all of them in 1 reducer and then do the cat of top-N.
>
> Wondering if there is any better approach to do this ?
>
> Regards
> Praveenesh

--
Harsh J