On Apr 17, 2010, at 11:09 AM, Eric Casteleijn wrote:
> On 04/16/2010 04:46 AM, wolfgang haefelinger wrote:
>> Thanks Robert
>>
>> for your answer. However, it is not exactly what I was looking for
>> (due to my inappropriate problem description).
>>
>> Firstly, I do want to have the document instead of the time stamp in
>> order to avoid that additional document fetch. That's obviously easy
>> to fix:
>>
>> function(doc) { //
>> emit([doc.name, doc.timestamp], doc);
>> }
>
> Don't do that, it's unnecessary, because you can always call any view with
> '?include_docs=true' and it will add a 'doc' member to each row, containing
> the document, and worse than that, it's harmful, as it makes the indexes
> stored on disk many times larger than they need to be. (Depending on the size
> of your documents this can really make a huge difference, anecdotal evidence
> suggests: gwibber used to do this, and when I changed it, the indexes stored
> on disk decreased some 90% in size.)
>
> If you always want the whole document, just emit null for a value and always
> call the view with include_docs.
>
> If there are cases where you don't want the whole document, decide which data
> you need and only emit that.
Hi Eric, I don't think its correct to have a blanket recommendation to always
use include_docs=true. For large range queries on a view the query performance
will be much better - up to 10x better throughput on large DBs in my experience
- if the doc is already included. Yes, the view index will balloon in size,
but some people may be willing to make that tradeoff. Cheers,
Adam
>
> --
> eric casteleijn
> https://code.launchpad.net/~thisfred
> Canonical Ltd.
>
