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Subject: Re: Multiple map reduce stages
From: J Chris Anderson <jchris@gmail.com>
In-Reply-To: <4BF26365.7030201@microlution.de>
Date: Tue, 18 May 2010 11:16:53 -0700
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References: <4BF26365.7030201@microlution.de>
To: user@couchdb.apache.org


On May 18, 2010, at 2:52 AM, Kropp, Henning wrote:

> Hi,
>=20
> as far as I know working with map reduce commonly involves multiple =
map
> and reduce stages. A view in couchdb solely consists of one map and if
> necessary one reduce stage!? To have multiple map and reduce stages =
one
> would have to conjunct views in couchdb!? How can I do that? Is it
> possible to give the function(doc){..} another parameter? There is the
> shows which have the extra parameter req for the http request.
> Unfortunately my javascript knowledge of the underlaying Prototype
> concept is not very funded which could be helpful here?
>=20
> Kind regards and many thanks in advanced


CouchDB Map Reduce is a realtime incremental model, so it is quite =
different from the Hadoop-style batch model. Of course you can still =
chain map reduce by copying the rows from a view query to a new db, and =
writing another view on the new db.

Chris=