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From Torstein Krause Johansen <torsteinkrausew...@gmail.com>
Subject Re: Complex queries & results
Date Tue, 07 Jun 2011 06:21:32 GMT
Hi Sean,

and thank you so much for your reply.

On 06/06/11 22:09, Sean Copenhaver wrote:

> Anyway, back to what you are trying to accomplish. Honestly it sounds like
> you are trying to get too advanced for the built-in _count or _sum reduce
> functions. Have you tried writing a custom reduce function that does the
> grouping how you want, basically by name alone?
>
> https://gist.github.com/1010318
>
> I tried this out with 10 docs fitting your example structure and with a
> plain query (no grouping, no filtering, reduce on) I get back:
>
> { John: 4, Jane: 6 }

Looks spot on! Thank you _so_ much for doing this.

I'm really curious how this performs, I will be-siege my couch with bulk 
updates, giving it a big-ish data set while simultaneously be-siege it 
with reads GETs querying this map/reduce you've created. Will be very 
interesting.

I'm still puzzled, though. When reading up on reduces, I got put off 
doing anything fancy in the reduce function as the guide on 
http://guide.couchdb.org/draft/views.html#example/3 states:

"A common mistake new CouchDB users make is attempting to construct 
complex aggregate values with a reduce function. Full reductions should 
result in a scalar value, like 5, and not, for instance, a JSON hash 
with a set of unique keys and the count of each."

And from my understanding, this is exactly what I want to do here, but 
perhaps I'm misunderstanding the author's meaning here?

Cheers,

-Torstein

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