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https://issues.apache.org/jira/browse/AMQ-4122?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13493533#comment-13493533
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Kyle Miller commented on AMQ-4122:
----------------------------------
I looked at things a bit closer and realized that there is a bug that is
contributing to this behavior.
org.apache.activemq.broker.LockableServiceSupport has a private BrokerService
variable. It implements BrokerServiceAware and has a method
setBrokerService(...).
org.apache.activemq.store.jdbc.JDBCPersistenceAdapter (which extends from
LockableServiceSupport) ALSO has a private BrokerService variable. It ALSO
implements BrokerServiceAware and has a method setBrokerService(...). Because
it extends from LockableServiceSupport, it overrides the setter and
consequently, the private BrokerService variable will NEVER be set.
I think that the JDBCPersistenceAdapter class should get rid of its private
BrokerService variable (and setter). This will solve the issue that I was
seeing with 2 active master brokers.
> Lease Database Locker failover broken
> -------------------------------------
>
> Key: AMQ-4122
> URL: https://issues.apache.org/jira/browse/AMQ-4122
> Project: ActiveMQ
> Issue Type: Bug
> Affects Versions: 5.7.0
> Environment: Java 7u9, SUSE 11, Mysql
> Reporter: st.h
> Assignee: Gary Tully
> Attachments: activemq-kyle.xml, activemq.xml, activemq.xml
>
>
> We are using ActiveMQ 5.7.0 together with a mysql database and could not
> observe correct failover behavior with lease database locker.
> It seems that there is a race condition, which prevents the correct failover
> procedure.
> We noticed that when starting up two instances, both instance are becoming
> master.
> We did several test, including the following and could not observe intended
> functionality:
> - shutdown all instances
> - manipulate database lock that one node has lock and set expiry time in
> distance future
> - start up both instances. both instances are unable to acquire lock, as the
> lock hasn't expired, which should be correct behavior.
> - update the expiry time in database, so that the lock is expired.
> - first instance notices expired lock and becomes master
> - when second instance checks for lock, it also updates the database and
> becomes master.
> To my understanding the second instance should not be able to update the
> lock, as it is held by the first instance and should not be able to become
> master.
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