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Date: Fri, 26 Feb 2010 13:03:05 -0500
Message-ID: <46aeb24f1002261003n3b3cb481w3e47ac69d6ac185b@mail.gmail.com>
Subject: Re: Consistent version of a view across multiple queries?
From: Robert Newson <robert.newson@gmail.com>
To: user@couchdb.apache.org
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You can query with stale=3Dok and the view won't change (as long as no
other call happens without stale=3Dok). You'll have to call without
stale=3Dok sometimes, though, so you'll still need to take care. Does
that help?

B.

On Fri, Feb 26, 2010 at 11:27 AM, Jens Alfke <jens@mooseyard.com> wrote:
> If an app wants to iterate over a large view, it seems better to page the=
 output by issuing multiple queries, using the startkey=3D and limit=3D par=
ameters. However, this seems to introduce race conditions if another client=
 is meanwhile altering the database. I might see half of the documents befo=
re the change and half after. For example, I might see a document show up t=
wice with two different key values.
>
> Is there any way to avoid this inconsistency? In a SQL database I'd use a=
 transaction for this, to lock out any database updates in between my serie=
s of SELECTs. But CouchDB's architecture doesn't support that.
>
> It seems like what I want is to specify some kind of clock (timestamp / r=
evision #) in my view queries, so they all run over the exact same view b-t=
ree. This seems straightforward at the level of the CouchDB file-format, si=
nce it's append-only and the previous view b-tree still exists in the file.=
 But is this exposed in the API at all?
>
> =97Jens