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 70770DBB8 for ; Thu, 20 Sep 2012 06:22:46 +0000 (UTC) Received: (qmail 35634 invoked by uid 500); 20 Sep 2012 06:22:44 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 35616 invoked by uid 500); 20 Sep 2012 06:22:44 -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 35595 invoked by uid 99); 20 Sep 2012 06:22:43 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 20 Sep 2012 06:22:43 +0000 X-ASF-Spam-Status: No, hits=-0.7 required=5.0 tests=FSL_RCVD_USER,RCVD_IN_DNSWL_LOW,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of scode@scode.org designates 209.85.217.172 as permitted sender) Received: from [209.85.217.172] (HELO mail-lb0-f172.google.com) (209.85.217.172) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 20 Sep 2012 06:22:35 +0000 Received: by lboj14 with SMTP id j14so1594434lbo.31 for ; Wed, 19 Sep 2012 23:22:14 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:sender:x-originating-ip:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:content-type :x-gm-message-state; bh=x16v0Y1qGc/d6pja5H87VVF+cpGVClM+9szEqdEAN/c=; b=NRP4mVjLwiTpt3+q+c5gUVlFMTtPz1x46bgfT0CEqadpBd7HcMlFPUEswzqTX4VsTX 3MPeYLgAmx2o6Ch/oAgsLcSIi6rmgundEKn/GpHHLYOqQxJ+VjVkjE7w8K5yzvhtMacC q72kZizs8Ds3eKAUgJCIWl/jEcxRKBkT0lKbomEaMZgkJhbsZYQGsnXClqjwRGXGfzEE 20l7yzsyg4DJGsSmZMMYJtsTxtv+PZMpcrjpxeOmHbKy1JBJg9zCAClX3UbXTmIq5SYL 0PR8G119ku87phVP+g1B4rnYCM6dQYIYFl480dze/X8YWARwo0jk7SYfZRFSEOGMPIZs czYA== MIME-Version: 1.0 Received: by 10.112.29.104 with SMTP id j8mr302634lbh.127.1348122134084; Wed, 19 Sep 2012 23:22:14 -0700 (PDT) Sender: scode@scode.org Received: by 10.114.5.69 with HTTP; Wed, 19 Sep 2012 23:22:14 -0700 (PDT) X-Originating-IP: [71.198.224.174] In-Reply-To: References: <50489C02.2030507@filez.com> Date: Wed, 19 Sep 2012 23:22:14 -0700 X-Google-Sender-Auth: 2STEQPCpFLKBjb6m5X9YhDhsAo0 Message-ID: Subject: Re: Invalid Counter Shard errors? From: Peter Schuller To: user@cassandra.apache.org Content-Type: text/plain; charset=UTF-8 X-Gm-Message-State: ALoCoQnwazcKO9XNrQckt1/EMlZQpXF2/mv+JBP3qzBaFdwOEIh2uNjrnzVVlCQQ8QNrIBBldLmf The significance I think is: If it is indeed the case that the higher value is always *in fact* correct, I think that's inconsistent with the hypothesis that unclean shutdown is the sole cause of these problems - as long as the client is truly submitting non-idempotent counter increments without a read-before-write. As a side note: If hou're using these counters for stuff like determining amounts of money to be payed by somebody, consider the non-idempotense of counter increments. Any write that increments a counter, that fails by e.g. Timeout *MAY OR MAY NOT* have been applied and cannot be safely retried. Cassandra counters are generally not useful if *strict* correctness is desired, for this reason. -- / Peter Schuller (@scode, http://worldmodscode.wordpress.com)