Return-Path: X-Original-To: apmail-cassandra-commits-archive@www.apache.org Delivered-To: apmail-cassandra-commits-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id D800CD065 for ; Wed, 27 Feb 2013 05:18:14 +0000 (UTC) Received: (qmail 16826 invoked by uid 500); 27 Feb 2013 05:18:14 -0000 Delivered-To: apmail-cassandra-commits-archive@cassandra.apache.org Received: (qmail 16765 invoked by uid 500); 27 Feb 2013 05:18:14 -0000 Mailing-List: contact commits-help@cassandra.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@cassandra.apache.org Delivered-To: mailing list commits@cassandra.apache.org Received: (qmail 16751 invoked by uid 99); 27 Feb 2013 05:18:14 -0000 Received: from arcas.apache.org (HELO arcas.apache.org) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 27 Feb 2013 05:18:14 +0000 Date: Wed, 27 Feb 2013 05:18:14 +0000 (UTC) From: "Jonathan Ellis (JIRA)" To: commits@cassandra.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (CASSANDRA-5062) Support CAS MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 [ https://issues.apache.org/jira/browse/CASSANDRA-5062?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13588007#comment-13588007 ] Jonathan Ellis commented on CASSANDRA-5062: ------------------------------------------- bq. The thing that is stopping me from hacking together a Paxos prototype is, where do we store the accepted-but-not-committed proposals? Thinking that just dumping them to a separate file (like the pre-2.0 manifest) will be adequate to start with. We can also trade off how fine-grained the paxos ensemble is (one per row, vs one per vnode) for storage space. > Support CAS > ----------- > > Key: CASSANDRA-5062 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5062 > Project: Cassandra > Issue Type: New Feature > Components: API, Core > Reporter: Jonathan Ellis > Fix For: 2.0 > > > "Strong" consistency is not enough to prevent race conditions. The classic example is user account creation: we want to ensure usernames are unique, so we only want to signal account creation success if nobody else has created the account yet. But naive read-then-write allows clients to race and both think they have a green light to create. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira