[AMQ-3681] DatabaseLocker should first cancel locking SQL statement before closing the SQL connection

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 5.4.2
• Fix Version/s: 5.6.0
• Component/s: Broker

Environment

ServiceMix 4.3

• Patch Info: Patch Available
• Assignee: Robert Davies
• Reporter: metatech
• Created: 25/Jan/12 14:41
• Updated: 16/Apr/12 13:29
• Resolved: 16/Apr/12 13:29

Description

ActiveMQ is configured in a Master/Slave configuration with an Oracle database :
http://activemq.apache.org/jdbc-master-slave.html
http://servicemix.apache.org/clustering.html
When the slave node is stopping, "activemq-broker" stays forever in the "Stopping" state.
This is because the locking SQL statement cannot be interrupted by just closing the JDBC connection. It is also needed to "cancel" the SQL statement.
Here is a patch to DefaultDatabaseLocker which makes it compatible with Oracle.
Thanks.

"Thread-92" prio=10 tid=0x08c4d800 nid=0x1036 waiting for monitor entry [0x8ab3a000]
   java.lang.Thread.State: BLOCKED (on object monitor)
	at oracle.jdbc.driver.PhysicalConnection.isClosed(PhysicalConnection.java:1223)
	- waiting to lock <0xad4367e0> (a oracle.jdbc.driver.T4CConnection)
	at org.apache.commons.dbcp.DelegatingConnection.isClosed(DelegatingConnection.java:386)
	at org.apache.commons.dbcp.DelegatingConnection.isClosed(DelegatingConnection.java:386)
	at org.apache.commons.dbcp.PoolingDataSource$PoolGuardConnectionWrapper.isClosed(PoolingDataSource.java:201)
	at org.apache.activemq.store.jdbc.DefaultDatabaseLocker.stop(DefaultDatabaseLocker.java:137)
	at com.mycompany.PoolCloser.close(PoolCloser.java:77)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.apache.aries.blueprint.utils.ReflectionUtils.invoke(ReflectionUtils.java:221)
	at org.apache.aries.blueprint.container.ServiceListener.invokeMethod(ServiceListener.java:98)
	at org.apache.aries.blueprint.container.ServiceListener.unregister(ServiceListener.java:65)

Issue Links

• is required by: AMQ-3696 Slave broker cannot be stopped in a JDBC Master/Slave configuration within OSGi
• relates to: AMQ-3654 JDBC Master/Slave : Slave cannot acquire lock when the master loose database connection.