Mailing-List: contact user-help@couchdb.apache.org; run by ezmlm
Precedence: bulk
Reply-To: user@couchdb.apache.org
Received-SPF: pass (athena.apache.org: domain of jchris@gmail.com designates
 209.85.222.182 as permitted sender)
DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=gamma;
        h=mime-version:sender:in-reply-to:references:date
         :x-google-sender-auth:message-id:subject:from:to:content-type;
        b=ZJq0FZ3wnvAPs2IeZXi4KxP0+MIq6uQU12/y/OHK+vai701fdmHtn1PDRZ2PkpA0uX
         9rN9aY8WJlZIOeO8H11RABYq1TdSxbiY8Cj8vxTt2MKLjHCUv5tDBBuCFvLYgAKTvY6W
         rPkNN1sf25OV4qCqgjF6zz+glbdUDvpcLZkHQ=
MIME-Version: 1.0
Sender: jchris@gmail.com
In-Reply-To: <hheal6$786$1@ger.gmane.org>
References: <E047F0C0-6535-4D74-88A1-41C6992B1867@gmail.com>
	 <6ebae6780912271244p3bbb4648t301fe0f85dbd6519@mail.gmail.com>
	 <hheal6$786$1@ger.gmane.org>
Date: Tue, 29 Dec 2009 17:50:49 -0800
Message-ID: <e282921e0912291750h281a7358t49edae78707e550e@mail.gmail.com>
Subject: Re: atomic/concurrent update_seq for _changes
From: Chris Anderson <jchris@apache.org>
To: user@couchdb.apache.org
Content-Type: text/plain; charset=ISO-8859-1

On Tue, Dec 29, 2009 at 5:33 PM, Joscha Feth <joscha@feth.com> wrote:
> Joscha Feth wrote:
>
>> I am doing exactly the same in my application and the gap between #1
>> and #2 also worried me - a special header sounds like a feasible
>> solution and I can't see any downside besides the few bytes of
>> overhead in the header for each request.
>
>
> Just for the record: you can create a custom list/show function, which
> adds the header:
>
> "lists": {
> mylist : "function(head, req) { start({\"code\": 200, \"headers\":
> {\"X-Update-Seq\": (\"\"+req.info.update_seq)}}); send(\"whatever\"); }"
> }
>
> One comment: you need to convert the update_seq into a string before
> sending it back via start() - might be a bug.
>

I think a fine way to add this information would be in the JSON view
response body itself, something like:

{"total_rows":1000,"offset":0, "update_seq": 1001, "rows":[
{"id":"1","key":1,"value":null},
...

This patch should be among the more trivial for a new Erlang / CouchDB
author to implement.

I see no reason not to add this feature. If anyone wants to implement,
and has questions or needs help getting started, the dev@ mailing list
is the place.

Cheers,
Chris

> regards,
> Joscha
>
> --
>
>
>


-- 
Chris Anderson
http://jchrisa.net
http://couch.io