From cassandra-user-return-1689-apmail-incubator-cassandra-user-archive=incubator.apache.org@incubator.apache.org Mon Dec 07 14:45:39 2009 Return-Path: Delivered-To: apmail-incubator-cassandra-user-archive@minotaur.apache.org Received: (qmail 46095 invoked from network); 7 Dec 2009 14:45:39 -0000 Received: from hermes.apache.org (HELO mail.apache.org) (140.211.11.3) by minotaur.apache.org with SMTP; 7 Dec 2009 14:45:39 -0000 Received: (qmail 37542 invoked by uid 500); 7 Dec 2009 14:45:39 -0000 Delivered-To: apmail-incubator-cassandra-user-archive@incubator.apache.org Received: (qmail 37523 invoked by uid 500); 7 Dec 2009 14:45:39 -0000 Mailing-List: contact cassandra-user-help@incubator.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: cassandra-user@incubator.apache.org Delivered-To: mailing list cassandra-user@incubator.apache.org Received: (qmail 37514 invoked by uid 99); 7 Dec 2009 14:45:39 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 07 Dec 2009 14:45:38 +0000 X-ASF-Spam-Status: No, hits=2.2 required=10.0 tests=HTML_MESSAGE,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of rantav@gmail.com designates 209.85.218.210 as permitted sender) Received: from [209.85.218.210] (HELO mail-bw0-f210.google.com) (209.85.218.210) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 07 Dec 2009 14:45:30 +0000 Received: by bwz2 with SMTP id 2so3720267bwz.20 for ; Mon, 07 Dec 2009 06:45:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type; bh=lh2pGNs8qZJQjDHn7EHboWV2sPtd06jP5lUGlSxXlM8=; b=PyD0h5exaSbeTI40Cnfrv194b/PXsNCdyHy4XUdAzTLZp2paZuXFRX4XhWHsgsl3qq BwIuS+u5B5tPNXOZi8BBM1t9IO84rcoUqKZUqdUYWmz56MLfuPjnw9j0G8rTeQhGqbKT BjvEYahYpVyFmFRSRu3m78jNGpoGpwB8CawTQ= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=tu/V3NTysu+eMNRYTxGJRHe1gdcFVoQT06UUAqJRu366Jp+iVLjDF1pAPOedgILHQu mvMZ8jvw8ZNM1E32ubs+9J/B6Ptryb9o29ftKVAVPkQ1eTMtAQkmloet4u+t2JWKs74W WUHpws+DY5V70cMw29l5QACZnuv+mGr9LW3rQ= MIME-Version: 1.0 Received: by 10.204.34.14 with SMTP id j14mr2444060bkd.76.1260197110407; Mon, 07 Dec 2009 06:45:10 -0800 (PST) In-Reply-To: <9e9cb550912061434g96cb59j100cb985a1186e0b@mail.gmail.com> References: <9e9cb550912061434g96cb59j100cb985a1186e0b@mail.gmail.com> Date: Mon, 7 Dec 2009 16:45:10 +0200 Message-ID: Subject: Re: vector clocks? From: Ran Tavory To: cassandra-user@incubator.apache.org Content-Type: multipart/alternative; boundary=0022154015be1ce213047a24817f X-Virus-Checked: Checked by ClamAV on apache.org --0022154015be1ce213047a24817f Content-Type: text/plain; charset=UTF-8 So, currently, is Cassandra using the client provided timestamps for conflict resolution? (Or something else?) Do clients have insight to conflicts Cassandra cannot resolve (assuming it tries to resolve them)? What's the semantic of "eventual consistency" in Cassandra's case then? On Mon, Dec 7, 2009 at 12:34 AM, Kelvin Kakugawa wrote: > Cassandra, right now, doesn't use vector clocks internally. However, > an implementation is being worked on, here: > https://issues.apache.org/jira/browse/CASSANDRA-580 > > -Kelvin > > On Sun, Dec 6, 2009 at 10:41 AM, Ran Tavory wrote: > > As a Cassandra newbe, after having read the Dynamo paper, I was wondering > - > > how does Cassandra use timestamps? > > - Does it use them internally to resolve conflicts? > > - Does it expose vector clocks to clients when internal conflict > resolution > > fails? > > Thanks > > > --0022154015be1ce213047a24817f Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
So, currently, is Cassandra using the client provided time= stamps for conflict resolution? (Or something else?)
Do clients have in= sight to conflicts Cassandra cannot resolve (assuming it tries to resolve t= hem)?
What's the semantic of "eventual consistency" in Cassand= ra's case then?

On Mon, Dec 7, 2009 a= t 12:34 AM, Kelvin Kakugawa <kakugawa@gmail.com> wrote:
Cassandra, right now, doesn't use vecto= r clocks internally. =C2=A0However,
an implementation is being worked on, here:
https://issues.apache.org/jira/browse/CASSANDRA-580

-Kelvin

On Sun, Dec 6, 2009 at 10:41 AM, Ran Tavory <rantav@gmail.com> wrote:
> As a Cassandra newbe, after having read the Dynamo paper, I was wonder= ing -
> how does Cassandra use timestamps?
> - Does it use them internally to resolve conflicts?
> - Does it expose vector clocks to clients when internal conflict resol= ution
> fails?
> Thanks
>

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