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Message-ID: <826304a60809212115p6c7cfdc6h8ee9395a0b986f90@mail.gmail.com>
Date: Mon, 22 Sep 2008 00:15:31 -0400
From: "Qin Gao" <qing@cs.cmu.edu>
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To: core-user@hadoop.apache.org
Subject: Re: is combiner output written to disk?
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I think it will be written to disk. There will be no difference in output
format or flow with or without combiner.

On Mon, Sep 22, 2008 at 12:08 AM, Sandy <snickerdoodle08@gmail.com> wrote:

> Just a quick clarification:
>
> The combiner function acts as an optimization between the map and the
> reduce
> phases. Is the output of the combiner phase stored in memory before being
> handed to reduce? Or is it written to disk and subsequently read from disk
> by the reduce phase?
>
>
> Thanks in advance,
>
> -SM
>

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