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From: Antony Blakey <antony.blakey@gmail.com>
To: user@couchdb.apache.org,
 Chris Anderson <jchris@gmail.com>
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Subject: Re: couchdb
Date: Sun, 21 Dec 2008 20:38:42 +1030
References: <494D94AF.8040305@timparkin.co.uk>
 <27BFB81F-9AE2-419C-8911-3F26D82A7A44@gmail.com>
 <e282921e0812202335ra39a176wb2a38c46fda64f24@mail.gmail.com>


On 21/12/2008, at 6:05 PM, Chris Anderson wrote:

> I think you are right on about no
> synchronous guarantees between updates, and code in external being
> run. Marking as dirty is a good way to handle this.

Without some timing guarantee I think even setting dirty is  
problematic, because it's possible to set a dirty flag from a  
notification, and yet have a request from the external (e.g. all docs  
by seq) see a both the dirty flag and pre-notification state, and  
hence cache old data thinking it's post-notification.

It's the avoidance of this kind of synchonisation problem that makes  
me think a UUID for the db and a UUID for the generation wrt  
compaction is a good idea. It reifies state boundaries in a way that  
can be used by external tools. I don't think there's any other way  
around it.

Antony Blakey
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