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From: Niket Patel <nexneo@me.com>
To: user@couchdb.apache.org
In-reply-to: <A0663BEB-B3C3-4D80-931C-D41A602AFFCE@apache.org>
Subject: Re: CouchDB huge performance difference between Mac OS / Linux
Date: Fri, 30 Jan 2009 19:21:49 +0530
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On Jan 30, 2009, at 5:37 PM, Jan Lehnardt wrote:

>
> Reduce functions should not grow its output larger
> than log(n) where n is the number of input rows.
>
> Can somebody update the wiki with that info, I thought
> we have it? :)

On wiki, this may not be mentioned but discussed on mailing list  
certainly many times.
Training one's procedural / OO brains to M/R/Rereduce with certain  
restrictions is not easy.

Well, in my case reduce output is may not be strictly following log(n)
But if you mean per Key , it is reducing to single row from any number  
of input rows for that key.

My problem seems to solve for now. with following change in M/R  
functions,

// from forEach loop ...
values.forEach(function(r) {
     ....
});

// to simple for loops ...
for( var i in values ){
     ....
}

I don't know what is cost of each approach.

I wish if couchdb handle this things more gracefully with descriptive  
errors.

Thanks for your answers.