From user-return-17975-apmail-cassandra-user-archive=cassandra.apache.org@cassandra.apache.org Tue Jun 21 21:32:16 2011 Return-Path: X-Original-To: apmail-cassandra-user-archive@www.apache.org Delivered-To: apmail-cassandra-user-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 75E67471D for ; Tue, 21 Jun 2011 21:32:16 +0000 (UTC) Received: (qmail 23665 invoked by uid 500); 21 Jun 2011 21:32:13 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 23627 invoked by uid 500); 21 Jun 2011 21:32:13 -0000 Mailing-List: contact user-help@cassandra.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@cassandra.apache.org Delivered-To: mailing list user@cassandra.apache.org Received: (qmail 23619 invoked by uid 99); 21 Jun 2011 21:32:13 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 21 Jun 2011 21:32:13 +0000 X-ASF-Spam-Status: No, hits=2.9 required=5.0 tests=HTML_MESSAGE,RCVD_IN_DNSWL_NONE,SPF_NEUTRAL X-Spam-Check-By: apache.org Received-SPF: neutral (athena.apache.org: local policy) Received: from [204.13.248.74] (HELO mho-02-ewr.mailhop.org) (204.13.248.74) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 21 Jun 2011 21:32:07 +0000 Received: from 67-6-215-137.hlrn.qwest.net ([67.6.215.137] helo=[192.168.0.2]) by mho-02-ewr.mailhop.org with esmtpsa (TLSv1:CAMELLIA256-SHA:256) (Exim 4.72) (envelope-from ) id 1QZ8Xy-000Ckw-Da for user@cassandra.apache.org; Tue, 21 Jun 2011 21:31:46 +0000 X-Mail-Handler: MailHop Outbound by DynDNS X-Originating-IP: 67.6.215.137 X-Report-Abuse-To: abuse@dyndns.com (see http://www.dyndns.com/services/mailhop/outbound_abuse.html for abuse reporting information) X-MHO-User: U2FsdGVkX1/x8k1gGKP9ohtEEmYmiKoewq28VQcoHS0= Message-ID: <4E010DBF.5060801@dude.podzone.net> Date: Tue, 21 Jun 2011 15:31:43 -0600 From: AJ User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.17) Gecko/20110414 Lightning/1.0b2 Thunderbird/3.1.10 MIME-Version: 1.0 To: user@cassandra.apache.org Subject: Re: Storing Accounting Data References: <4E00D52A.6040409@dude.podzone.net> <4E01073B.6090200@dude.podzone.net> In-Reply-To: Content-Type: multipart/alternative; boundary="------------040805040706050106030802" This is a multi-part message in MIME format. --------------040805040706050106030802 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit What's the best accepted way to handle that 100% in the client? Retries? On 6/21/2011 3:14 PM, Anand Somani wrote: > Not sure if it is that simple, a quorum can fail with writes happening > on some nodes (there is no rollback). Also there is no concept of > atomic compare-and-swap. > > On Tue, Jun 21, 2011 at 2:03 PM, AJ > wrote: > > On 6/21/2011 2:50 PM, Stephen Connolly wrote: >> >> how important are things like transactional consistency for you? >> >> would you have issues if only one side of a transfer was recorded? >> > > Right. Both of those questions are about consistency. Isn't the > simple solution is to use QUORUM read/writes? > >> cassandra, out of the box, on it's own, would not be ideal if the >> above two things are important for you. >> >> you can add components to a system to help address these things, >> eg zookeeper, etc. a reason why you moght do this is if you >> already use cassandra in your app and are trying to limit the >> number of databases >> >> - Stephen >> >> --- >> Sent from my Android phone, so random spelling mistakes, random >> nonsense words and other nonsense are a direct result of using >> swype to type on the screen >> >> On 21 Jun 2011 18:30, "AJ" > > wrote: > > --------------040805040706050106030802 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit What's the best accepted way to handle that 100% in the client?  Retries?

On 6/21/2011 3:14 PM, Anand Somani wrote:
Not sure if it is that simple, a quorum can fail with writes happening on some nodes (there is no rollback). Also there is no concept of atomic compare-and-swap.

On Tue, Jun 21, 2011 at 2:03 PM, AJ <aj@dude.podzone.net> wrote:
On 6/21/2011 2:50 PM, Stephen Connolly wrote:

how important are things like transactional consistency for you?

would you have issues if only one side of a transfer was recorded?


Right.  Both of those questions are about consistency.  Isn't the simple solution is to use QUORUM read/writes? 

cassandra, out of the box, on it's own, would not be ideal if the above two things are important for you.

you can add components to a system to help address these things, eg zookeeper, etc. a reason why you moght do this is if you already use cassandra in your app and are trying to limit the number of databases

- Stephen

---
Sent from my Android phone, so random spelling mistakes, random nonsense words and other nonsense are a direct result of using swype to type on the screen

On 21 Jun 2011 18:30, "AJ" <aj@dude.podzone.net> wrote:



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