From users-return-10559-apmail-openjpa-users-archive=openjpa.apache.org@openjpa.apache.org Mon Jan 14 20:42:54 2013 Return-Path: X-Original-To: apmail-openjpa-users-archive@minotaur.apache.org Delivered-To: apmail-openjpa-users-archive@minotaur.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 59908D246 for ; Mon, 14 Jan 2013 20:42:54 +0000 (UTC) Received: (qmail 67447 invoked by uid 500); 14 Jan 2013 20:42:54 -0000 Delivered-To: apmail-openjpa-users-archive@openjpa.apache.org Received: (qmail 67323 invoked by uid 500); 14 Jan 2013 20:42:53 -0000 Mailing-List: contact users-help@openjpa.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: users@openjpa.apache.org Delivered-To: mailing list users@openjpa.apache.org Received: (qmail 67305 invoked by uid 99); 14 Jan 2013 20:42:53 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 14 Jan 2013 20:42:53 +0000 X-ASF-Spam-Status: No, hits=1.5 required=5.0 tests=HTML_MESSAGE,RCVD_IN_DNSWL_LOW,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: domain of seba.wagner@gmail.com designates 209.85.216.176 as permitted sender) Received: from [209.85.216.176] (HELO mail-qc0-f176.google.com) (209.85.216.176) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 14 Jan 2013 20:42:48 +0000 Received: by mail-qc0-f176.google.com with SMTP id n41so2735704qco.21 for ; Mon, 14 Jan 2013 12:42:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:from:date:message-id:subject:to:cc:content-type; bh=VwCLh2jUolcAjsFX6V7I91c8XQ0ARjX2/mGUVR0DryI=; b=pYrfPmqIKLAa+dmrBvB9Ndjcbir9GyEuwUMXkeQoKUHW11fIXerJy9gO+D9eWRQwfN RQ8NpKfUb36u5JYMHmmOUmKcMzk6RkLeo47SDmrsamK4xpG8oj6B5RZP/FypBJ3dLoVh srv4sWDKhNXrmj1LWd+UJlmm5p+juXeAyrQ/QRlP1Ia+fMggIxzdMefTQNS7GNEH5GE3 R4F9jVKpiqcADxoKmWOYPZ/NssEq2ZCphTyZ+PgZz8kGsEz9xeEnPQqklnFS8tWVrX53 uPVxMUf4kJa9y4/Yw9aX1j60eJdvos9kSYer6QKQZsbcTosQIwOZgIK1REYQ1OJ1gcWN CN+Q== Received: by 10.229.196.166 with SMTP id eg38mr17807457qcb.84.1358196147236; Mon, 14 Jan 2013 12:42:27 -0800 (PST) MIME-Version: 1.0 Received: by 10.49.116.103 with HTTP; Mon, 14 Jan 2013 12:42:06 -0800 (PST) From: "seba.wagner@gmail.com" Date: Tue, 15 Jan 2013 09:42:06 +1300 Message-ID: Subject: OpenJPA Clustering (and MySQL Replication) To: users@openjpa.apache.org Cc: "openmeetings-dev@incubator.apache.org" Content-Type: multipart/alternative; boundary=005045015e46e42fbb04d345aef1 X-Virus-Checked: Checked by ClamAV on apache.org --005045015e46e42fbb04d345aef1 Content-Type: text/plain; charset=ISO-8859-1 Hi, we are currently drafting/implementing some clustering mechanisms for Apache OpenMeetings. I have seen OpenJPA supports the MySQL Replication feature: http://people.apache.org/~mikedd/nightly.builds/apache-openjpa-2.3.0-SNAPSHOT/docs/docbook/manual/ref_guide_dbsetup_dbsupport.html#ref_guide_dbsetup_dbsupport_mysql which is great! However it solves only one side of the cluster: Having the database clustered. What happens if you want to cluster OpenJPA itself on multiple nodes? Each OpenJPA instance would have its own data-cache, how can you make sure those caches are synchronized across all nodes in your cluster? And how would you solve the primary key/sequencer issue? When multiple instances write to the same database they could potentially try to create a record with the same primary key. Thanks! Sebastian -- Sebastian Wagner https://twitter.com/#!/dead_lock http://www.webbase-design.de http://www.wagner-sebastian.com seba.wagner@gmail.com --005045015e46e42fbb04d345aef1--