Return-Path: X-Original-To: apmail-activemq-commits-archive@www.apache.org Delivered-To: apmail-activemq-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 61CB9EAEB for ; Mon, 25 Feb 2013 14:22:23 +0000 (UTC) Received: (qmail 45880 invoked by uid 500); 25 Feb 2013 14:22:23 -0000 Delivered-To: apmail-activemq-commits-archive@activemq.apache.org Received: (qmail 45828 invoked by uid 500); 25 Feb 2013 14:22:22 -0000 Mailing-List: contact commits-help@activemq.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@activemq.apache.org Delivered-To: mailing list commits@activemq.apache.org Received: (qmail 45805 invoked by uid 99); 25 Feb 2013 14:22:21 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 25 Feb 2013 14:22:21 +0000 X-ASF-Spam-Status: No, hits=-2000.0 required=5.0 tests=ALL_TRUSTED X-Spam-Check-By: apache.org Received: from [140.211.11.4] (HELO eris.apache.org) (140.211.11.4) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 25 Feb 2013 14:22:19 +0000 Received: from eris.apache.org (localhost [127.0.0.1]) by eris.apache.org (Postfix) with ESMTP id 50F692388900 for ; Mon, 25 Feb 2013 14:21:59 +0000 (UTC) Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: svn commit: r851880 - in /websites/production/activemq/content: cache/main.pageCache pluggable-storage-lockers.html Date: Mon, 25 Feb 2013 14:21:59 -0000 To: commits@activemq.apache.org From: buildbot@apache.org X-Mailer: svnmailer-1.0.8-patched Message-Id: <20130225142159.50F692388900@eris.apache.org> X-Virus-Checked: Checked by ClamAV on apache.org Author: buildbot Date: Mon Feb 25 14:21:58 2013 New Revision: 851880 Log: Production update by buildbot for activemq Modified: websites/production/activemq/content/cache/main.pageCache websites/production/activemq/content/pluggable-storage-lockers.html Modified: websites/production/activemq/content/cache/main.pageCache ============================================================================== Binary files - no diff available. Modified: websites/production/activemq/content/pluggable-storage-lockers.html ============================================================================== --- websites/production/activemq/content/pluggable-storage-lockers.html (original) +++ websites/production/activemq/content/pluggable-storage-lockers.html Mon Feb 25 14:21:58 2013 @@ -138,15 +138,15 @@ In addition, where the database supports

<persistenceAdapter>
-	<jdbcPersistenceAdapter dataDirectory="${activemq.data}" dataSource="#mysql-ds" lockKeepAlivePeriod="10000">
+	<jdbcPersistenceAdapter dataDirectory="${activemq.data}" dataSource="#mysql-ds" lockKeepAlivePeriod="5000">
 		<locker>
-			<lease-database-locker lockAcquireSleepInterval="5000"/>
+			<lease-database-locker lockAcquireSleepInterval="10000"/>
 		</locker>
 	</jdbcPersistenceAdapter>
 </persistenceAdapter>

The lease based lock is acquired by blocking at start and retained by the keepAlivePeriod. To retain, the lease is extended by the lockAcquireSleepInterval, so in theory the master is always (lockAcquireSleepInterval-lockKeepAlivePeriod) ahead of the slave w.r.t the lease. It is imperative that lockAcquireSleepInterval > lockKeepAlivePeriod, to ensure the lease is always current.
In the simplest case, the clocks between master and slave must be in sync for this solution to work properly. If the clocks cannot be in sync, the locker can use the system time from the database CURRENT TIME and adjust the timeouts in accordance with their local variance from the db system time. If maxAllowableDiffFromDBTime is > 0 the local periods will be adjusted by any delta that exceeds maxAllowableDiffFromDBTime.