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https://issues.apache.org/activemq/browse/AMQ-992?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Kenny MacLeod reopened AMQ-992:
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I'm re-opening this issue because it may be that the fix was unnecessary. In
MySQL, SELECT FOR UPDATE only works with InnoDB tables. The default table type
in MySQL - MyISAM - does not support SELECT FOR UPDATE - it executes the
select, but doesn't hold the lock, resulting in Steven's problem. There's no
need for specific MySQL behaviour here.
However, when it comes to creating the tables, MySQL will create the table
according to the server's default table type, which is MyISAM unless specific
in MySQL's startup config. Ideally, ActiveMQ would specify InnoDB in the
CREATE TABLE clause.
> MySQL doesn't honor lock in JDBC Master Slave configuration?
> ------------------------------------------------------------
>
> Key: AMQ-992
> URL: https://issues.apache.org/activemq/browse/AMQ-992
> Project: ActiveMQ
> Issue Type: Bug
> Affects Versions: 4.1.0
> Environment: RHEL 4
> MySQL 4.x, 5.x
> mysql-ab_jdbc_driver
> Reporter: Steven Lotito
> Fix For: 4.1.1, 5.0.0
>
> Attachments: mysql_obtain_lock.txt
>
>
> I have been attempting to get the new 4.1 JDBC Master Slave configuration
> working with MySQL.
> The log from the first broker to start up states:
> 2006-10-18 09:35:08,558 [main ] INFO DefaultDatabaseLocker
> - Attempting to acquire the exclusive lock to become the Master broker
> 2006-10-18 09:35:08,559 [main ] INFO DefaultDatabaseLocker
> - Becoming the master on dataSource: [EMAIL PROTECTED]
> The 2nd broker to start up has an identical message and both brokers listen
> for connections.
> The 2nd broker should be waiting for the lock and NOT accepting connections,
> if I understand http://www.activemq.org/site/jdbc-master-slave.html
> correctly...
> Oracle exhibits the expected behavior:
> When running the exact same configuration (except using an Oracle
> datasource), the first broker has the same log message as above, while the
> 2nd broker halts at the "Attempting to acquire the exclusive lock to become
> the Master broker" message until I fail the master. Then it becomes the
> master.
> Is this a known issue? I was able to replicate it using both MySql 4 and 5
> (trying both the MySQL Connector/J 3.1 and MySQL Connector/J 5.0 drivers)
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