Mailing-List: contact couchdb-user-help@incubator.apache.org; run by ezmlm
Precedence: bulk
Reply-To: couchdb-user@incubator.apache.org
Received-SPF: pass (athena.apache.org: domain of kowsik@gmail.com designates
 74.125.92.150 as permitted sender)
DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=gamma;
        h=message-id:date:from:to:subject:in-reply-to:mime-version
         :content-type:content-transfer-encoding:content-disposition
         :references;
        b=KGgZ1FSYPnrWKAjYv835MzYw6SB433TDISCYCYdGd4cBNOZXn+GCF/vutxfp3qBTlp
         UqexeDeVupbIFZW74/4KkCnzvVhqe+NHhDBUk+jtpsVidrrVA8NLeB5mYLxV4VBs0mWu
         SVy9QR7bEe01dNIBtKWJNAdQPx3XvATEgaDNg=
Message-ID: <7db9abd30810231008y48d82461y576ed85a0d3692df@mail.gmail.com>
Date: Thu, 23 Oct 2008 10:08:02 -0700
From: kowsik <kowsik@gmail.com>
To: couchdb-user@incubator.apache.org
Subject: Re: Question on view server design...
In-Reply-To: <FF30523B-CD3A-49BE-AAA5-CEEC335CDA6A@apache.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
References: <7db9abd30810230935u266ebf9tc49cf8bf5e7838b7@mail.gmail.com>
	 <FF30523B-CD3A-49BE-AAA5-CEEC335CDA6A@apache.org>

No, not explicitly, but I was looking at evalcx which sets up and
tears down a new JSContext each time a function is compiled. Just
wondering if there's an incremental way of doing this so we don't
incur the overhead each time reduce is invoked.

Maybe with TraceMonkey, this is a moot point? ;-)

K.

On Thu, Oct 23, 2008 at 9:42 AM, Jan Lehnardt <jan@apache.org> wrote:
>
> On Oct 23, 2008, at 18:35, kowsik wrote:
>
>> I was seeing the couchjs process getting pegged and I was looking into
>> further.
>>
>> 1. The protocol uses "add_fun" command to add all the map functions to
>> the view server so that they are compiled and ready to go.
>> 2. Then "map_doc" is invoked with each document to return the results
>> of the various emit's
>> 3. They "reduce" and "rereduce" are invoked depending on the query.
>>
>> It's #3 that I'm interested in. The "reduce" command currently passes
>> in the reduce function string from the design view each time it's
>> invoked. This means the reduce function is first eval'd and then
>> executed. I'm wondering if it's possible to rename "add_fun" to
>> "add_map_fun" and introduce a new "add_reduce_fun" and then reference
>> functions by index? Seems like it might speed things up quite a bit.
>
> Have you measured the reduce function compilation to be a bottleneck?
> I'd guess (see, haven't measured either:-) that erlang-term to JSON & JSON
> parsing take up significantly more time.
>
> Cheers
> Jan
> --
>