[AMQ-5447] Memory Leak after shutdown embeded broker with JDBC persistence

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 5.10.0
• Fix Version/s: 5.11.0
• Component/s: Broker, Message Store

Environment

Windows7, JDK7

• Patch Info: Patch Available
• Assignee: Unassigned
• Reporter: Shi Lei
• Created: 21/Nov/14 07:32
• Updated: 25/Nov/14 19:56
• Resolved: 25/Nov/14 19:56

Description

After shutdown embeded activemq broker with JDBC store, 2 'ActiveMQ JDBC PA Scheduled Task' is still alive.
Because the 2 thread's Thread factory is object of JDBCPersistenceAdapter's inner class, so the object of JDBCPersistenceAdapter can be reached from the 2 threads, JDBCPersistenceAdapter has a field point to BrokerService. So the instance of BrokerService can be reached from the 2 threads.

So the stopped brokerService cannot be GC.

The root cause is that when stopping JDBCPersistenceAdapter, only cancelling cleanupTicket without shutdown clockDaemon, that's why the 2 threads are still alive.

According to http://activemq.apache.org/how-do-i-restart-embedded-broker.html, it's better (more reliable) to instantiate the broker again instead of reuse old broker. So if I restart embeded broker, there will be 1 more BrokerService in memory. I think it's memory leak.