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 2ABD77BEA for ; Fri, 22 Jul 2011 20:37:52 +0000 (UTC) Received: (qmail 40925 invoked by uid 500); 22 Jul 2011 20:37:50 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 40864 invoked by uid 500); 22 Jul 2011 20:37:49 -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 40753 invoked by uid 99); 22 Jul 2011 20:37:49 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 22 Jul 2011 20:37:49 +0000 X-ASF-Spam-Status: No, hits=-0.7 required=5.0 tests=FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS,T_TO_NO_BRKTS_FREEMAIL X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: domain of synfinatic@gmail.com designates 74.125.83.44 as permitted sender) Received: from [74.125.83.44] (HELO mail-gw0-f44.google.com) (74.125.83.44) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 22 Jul 2011 20:37:44 +0000 Received: by gwb20 with SMTP id 20so2104199gwb.31 for ; Fri, 22 Jul 2011 13:37:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :content-type:content-transfer-encoding; bh=31SGZeEWmuwlP3Lb+U8V3Ak5axAgjYKJGYbXmr6gtAY=; b=S6gqlb9H9iV0yKnFvlw10516QRT4Ez15OkFPzVuOlS8f00ztAj7AzCCufIhVojDL02 lsSz/n3QD43dJWYfqPbGy5Fik2XkTLGncYHRZW6VsZd4plABGuyx1fXKxSy2zOVSVr4O xDz4cY90/b+cJz/xOuiVzxXsbJ1rBH7499OCk= Received: by 10.146.14.34 with SMTP id 34mr1988690yan.34.1311367042866; Fri, 22 Jul 2011 13:37:22 -0700 (PDT) MIME-Version: 1.0 Received: by 10.147.171.12 with HTTP; Fri, 22 Jul 2011 13:37:02 -0700 (PDT) In-Reply-To: <4E29A50C.9080903@ihep.ac.cn> References: <4E29A50C.9080903@ihep.ac.cn> From: Aaron Turner Date: Fri, 22 Jul 2011 13:37:02 -0700 Message-ID: Subject: Re: [SPAM] Fwd: Counter consistency - are counters idempotent? To: user@cassandra.apache.org, zangds@ihep.ac.cn Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On Fri, Jul 22, 2011 at 9:27 AM, Donal Zang wrote: > On 22/07/2011 18:08, Yang wrote: >> >> btw, this "issue" of =A0not knowing whether a write is persisted or not >> when client reports error, is not limited to counters, =A0for regular >> columns, it's the same: if client reports write failure, the value may >> well be replicated to all replicas later. =A0this is even the same with >> all other systems: Zookeeper, Paxos, ultimately due to the FLP >> theoretical result of "no guarantee of consensus in async systems" > > yes, but with regular columns, retry is OK, while counter is not. I know I've heard that fixing this issue is "hard". I've assumed this to mean "don't expect a fix anytime soon". Is that accurate? Beginning to start having second thoughts that Cassandra is the right fit for my project which would heavily rely on counters to roll up aggregates. --=20 Aaron Turner http://synfin.net/=A0 =A0 =A0 =A0=A0 Twitter: @synfinatic http://tcpreplay.synfin.net/ - Pcap editing and replay tools for Unix & Win= dows Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety. =A0 =A0 -- Benjamin Franklin "carpe diem quam minimum credula postero"