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From kowsik <kow...@gmail.com>
Subject Re: Question on view server design...
Date Thu, 23 Oct 2008 17:08:02 GMT
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
> --
>

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