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From Niels Basjes <Ni...@basjes.nl>
Subject Re: How to select random n records using mapreduce ?
Date Mon, 27 Jun 2011 19:28:43 GMT
The only solution I can think of is by creating a counter in Hadoop
that is incremented each time a mapper lets a record through.
As soon as the value reaches a preselected value the mappers simply
discard the additional input they receive.

Note that this will not at all be random.... yet it's the best I can
come up with right now.


On Mon, Jun 27, 2011 at 09:11, Jeff Zhang <zjffdu@gmail.com> wrote:
> Hi all,
> I'd like to select random N records from a large amount of data using
> hadoop, just wonder how can I archive this ? Currently my idea is that let
> each mapper task select N / mapper_number records. Does anyone has such
> experience ?
> --
> Best Regards
> Jeff Zhang

Best regards / Met vriendelijke groeten,

Niels Basjes

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