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From Chris Anderson <>
Subject Re: couchdb on 8 core redhat/fedora
Date Sun, 09 Aug 2009 21:42:34 GMT
On Sun, Aug 9, 2009 at 2:25 PM, Nitin Borwankar<> wrote:
> On Sun, Aug 9, 2009 at 12:13 PM, Adam Kocoloski <> wrote:
>> Hi Nitin, Jan's right, if you're only building views from a single design
>> doc you won't get much indexing speedup from multi-core at the moment.  We
>> do spawn multiple couchjs processes (often one does the map and the other
>> the reduce), but we don't map docs out to them simultaneously or anything.
>>  Also, the Erlang process communicating with couchjs blocks and waits for
>> the results when it sends data out.  Best,
>> Adam
> Ok, so I could have multiple databases each with multiple design docs and
> make a number of requests and have a number of couchjs processes spread out
> across multiple cores right?
> I suppose what I am hearing is that views in a single design doc can become
> a bottleneck but views in multiple design docs will get the benefit of
> multiple couchjs processes.
> Since this part of my experiment is not couchapp based, I am completely fine
> having a) multiple databases and b) multiple design docs per database.

Unless you have lots of disks, you won't gain performance from
multiple dbs. However, you might do well you put views onto a
different disk from the db file, if you'll be writing while generating
indexes. or spread view files across disks with symlinks so disks
don't have to seek as much to record view rows.

> So this gives me the OS level scheduling of couchjs processes across cores,
> I think.
> Nitin
> 37% of all statistics are made up on the spot
> -------------------------------------------------------------------------------------
> Nitin Borwankar

Chris Anderson

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