From user-return-15755-apmail-couchdb-user-archive=couchdb.apache.org@couchdb.apache.org Sat Apr 09 10:00:29 2011 Return-Path: Delivered-To: apmail-couchdb-user-archive@www.apache.org Received: (qmail 39998 invoked from network); 9 Apr 2011 10:00:29 -0000 Received: from hermes.apache.org (HELO mail.apache.org) (140.211.11.3) by minotaur.apache.org with SMTP; 9 Apr 2011 10:00:29 -0000 Received: (qmail 86602 invoked by uid 500); 9 Apr 2011 10:00:27 -0000 Delivered-To: apmail-couchdb-user-archive@couchdb.apache.org Received: (qmail 86484 invoked by uid 500); 9 Apr 2011 10:00:27 -0000 Mailing-List: contact user-help@couchdb.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@couchdb.apache.org Delivered-To: mailing list user@couchdb.apache.org Received: (qmail 86471 invoked by uid 99); 9 Apr 2011 10:00:27 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Sat, 09 Apr 2011 10:00:27 +0000 X-ASF-Spam-Status: No, hits=0.7 required=5.0 tests=SPF_NEUTRAL X-Spam-Check-By: apache.org Received-SPF: neutral (athena.apache.org: local policy) Received: from [195.10.6.237] (HELO core.fluendo.com) (195.10.6.237) by apache.org (qpsmtpd/0.29) with ESMTP; Sat, 09 Apr 2011 10:00:21 +0000 Received: from otto.amantes (101.Red-81-33-163.dynamicIP.rima-tde.net [81.33.163.101]) by core.fluendo.com (Postfix) with ESMTP id DDF3E23A for ; Sat, 9 Apr 2011 11:59:57 +0200 (CEST) Received: from [127.0.0.1] (otto.amantes [127.0.0.1]) by otto.amantes (Postfix) with ESMTP id 24599140D44 for ; Sat, 9 Apr 2011 11:59:56 +0200 (CEST) Subject: Re: change notifications question From: Thomas Vander Stichele To: user@couchdb.apache.org In-Reply-To: References: <1302198233.3064.15.camel@ana.amantes> <1302338725.29780.6.camel@otto.amantes> Content-Type: text/plain; charset="UTF-8" Date: Sat, 09 Apr 2011 11:59:55 +0200 Message-ID: <1302343195.29780.9.camel@otto.amantes> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 (2.32.2-1.fc14) Content-Transfer-Encoding: 7bit On Sat, 2011-04-09 at 10:42 +0100, Robert Newson wrote: > CouchDB does not provide revisioning or history features to the end > user at all. This is a common mistake. > > The use of _rev and MVCC is purely a mechanism to enable sane > replication between servers where writes are permitted everywhere. > CouchDB's replication will only ensure that the current version* of > any document is replicated, earlier revisions are *not* replicated. I'm not interested in replicating earlier revisions. I'm interested in receiving the change notification (either because of replication or because of a local update) and showing what changed. I'm pretty sure that: - in the case of a local update, the previous revision is still there at the moment the change notification happens - in the case of a replication update, the previous local revision is still locally available too. Those are the changes I'm interested in showing, and hence I see no reason why couchdb couldn't inform both the new revid and the revid just before the change. > Earlier revisions are also removed on compaction, which is an > essential maintenance operation. Essential how ? It's not going to stop working if you don't compact, just slow down. Depends on your usage model. And in any case, compaction is triggered, so I would be completely ok with once in a while not being able to get an older revision and not correctly show changes because I triggered compaction. 99% of the time this wouldn't be the case. Thomas -- -- you own me there's nothing you can do you own me lucky you -- Flumotion - the only way to stream! http://www.flumotion.net/