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From: Damien Katz <damien@apache.org>
To: couchdb-user@incubator.apache.org
In-Reply-To: <492317D5.60300@silencegreys.com>
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Subject: Re: View with incremental counter
Date: Tue, 18 Nov 2008 14:35:22 -0500
References: <a95d32b00811180427n4b41c757xe8b2390a5a7428d1@mail.gmail.com>
	 <4922C646.7010802@silencegreys.com>
 <d6f4831c0811180651i5e6560eeqfffb97c817803042@mail.gmail.com>
 <492317D5.60300@silencegreys.com>

Spidermonkey's sandboxing capabilities vary release to release. As I  
recall, we had full sandboxing working with earlier releases, but  
something changed in 1.7 and we took it out.

-Damien

On Nov 18, 2008, at 2:30 PM, Jedediah Smith wrote:

>
> Grasping the concepts involved in map/reduce might end up being a  
> significant hurdle to CouchDB adoption so I would encourage features  
> that assist in that regard. Sandboxing might also be necessary to  
> enforce whatever is ultimately CouchDB's security model.
>
> Spidermonkey must have sandboxing capabilities if it runs the  
> javascript for both the Firefox browser and the web pages it loads.
>
> Paul's case of caching large objects is something to consider (and a  
> reason my previous email was not strictly correct) but could perhaps  
> be handled more formally or left to custom view servers.
>
> Benjamin Nortier wrote:
>> Should CouchDB not restrict defining state outside the map function?
>> I.e. you should not be able to declare a counter outside the  
>> function?
>> On Tue, Nov 18, 2008 at 1:42 PM, Jedediah Smith
>> <jedediah@silencegreys.com> wrote:
>>> You can't maintain a state across calls to map functions in this  
>>> way. Map
>>> functions can be called in any order or in parallel, any number of  
>>> times on
>>> a particular document and in completely separate environments.  
>>> They should
>>> not have any side effects or depend on any outside state.
>>>
>>> You should read up on Google's MapReduce and maybe functional  
>>> programming in
>>> general in order to understand how CouchDB works.
>>>
>>> If you just want to number the results of your view, that can be  
>>> easily done
>>> by the calling code.
>>>
>>> Adam Groves wrote:
>>>> Hi,
>>>>
>>>> I've got the following view:
>>>>
>>>> count = 0;
>>>> function(doc) {
>>>> if(doc.type == "document") {
>>>>   count = count + 1
>>>>   emit(doc._id, count);
>>>> }
>>>> }
>>>>
>>>> The idea is that I get a list of documents, each having a counter
>>>> value which is incremental. I expected the count values to come  
>>>> out in
>>>> order, but that isn't the case: my first few documents have  
>>>> values of
>>>> 62, 61, 22, 19. I'm not quite sure what's going on here - any ideas
>>>> how the order is being set here?
>>>>
>>>> Regards
>>>>
>>>> Adam Groves
>>>>