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From Zachary Zolton <>
Subject Re: group_level in reduce function
Date Wed, 24 Mar 2010 20:09:09 GMT
Folks who really need to chain map-reduced views have to hand-roll
their own solution. This usually involve some scripting to keep a
derived database up-to-date with the output of the source database's

On Wed, Mar 24, 2010 at 2:20 PM, Aurélien Bénel <> wrote:
> Thanks for your answer.
>> If you want to be able to be able to include the same piece of code in multiple views
> Good idea, I'll do that.
>> What do you mean by a script to "combine several views"?
> I mean that the implementations of algorithms that benefit from MapReduce (TF.IDF, Markov
chains, K nearest neighbors...) usually need to chain several MapReduces:  the input of a
map/reduce is generated by others. I still don't know how to do that in CouchDB.
> Regards,
> Aurélien

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