Hello again. Digging into the problem I've found another thing related
with an asymmetry in the way an advisory topic is created and destroyed.
I'm analizying the way the Consumer and Producer advisory topics for
temporary queues are created and destroyed:
An advisory topic is actually created when the AdvisoryBroker
fireAdvisory method is eventually sending the message. This is happening
in AbstractRegion lookup method, as the advisory topic doesn't exist yet:
protected Destination lookup(ConnectionContext context,
ActiveMQDestination destination) throws Exception {
synchronized(destinationsMutex){
Destination dest=(Destination) destinations.get(destination);
if(dest==null){
if(autoCreateDestinations){
// Try to auto create the destination... re-invoke
broker from the
// top so that the proper security checks are performed.
context.getBroker().addDestination(context,destination);
// We should now have the dest created.
dest=(Destination) destinations.get(destination);
}
if(dest==null){
throw new JMSException("The destination
"+destination+" does not exist.");
}
}
return dest;
}
}
Hence, the whole Broker chain is called to create a destination
(context.getBroker().addDestination), this, in a common environment,
involves calling:
MutableBrokerFilter.addDestination - Just pass the request to the next
chained BrokerFilter
[
Here the configured plugins
}
CompositeDestinationBroker. No implementation, so it passes the request
to the next chained object.
AdvisoryBroker. Fires an advisory to the destination advisory topic, and
adds the destination to its own destinations map.
TransactionBroker. No implementation, passes the request to the next
chained object.
RegionBroker. Delegates in the TopicRegion.addDestination to create the
given advisory topic.
On the other way, this advisory topic is destroyed when the advised
destination is removed, in AdvisoryTopic. removeDestinationInfo. But
here, the way to do it is:
public void removeDestinationInfo(ConnectionContext context,
DestinationInfo destInfo) throws Exception{
next.removeDestinationInfo(context, destInfo);
DestinationInfo info = (DestinationInfo)
destinations.remove(destInfo.getDestination());
if( info !=null ) {
info.setDestination(destInfo.getDestination());
info.setOperationType(DestinationInfo.REMOVE_OPERATION_TYPE);
ActiveMQTopic topic =
AdvisorySupport.getDestinationAdvisoryTopic(destInfo.getDestination());
fireAdvisory(context, topic, info);
try {
next.removeDestination(context,
AdvisorySupport.getConsumerAdvisoryTopic(info.getDestination()), -1);
} catch (Exception expectedIfDestinationDidNotExistYet) {
}
try {
next.removeDestination(context,
AdvisorySupport.getProducerAdvisoryTopic(info.getDestination()), -1);
} catch (Exception expectedIfDestinationDidNotExistYet) {
}
}
}
So, only the next chained broker components to AdvisoryBroker are called
to remove the consumer and producer advisory topics. This way to proceed
suggests me two problems:
1.-The advisory broker itself is not aware of the deletion of those
topics (remember that it had registered them when the whole broker chain
was called to create the topic). I think that this is the leakage I'm
suffering.
2.-Any plugin (or component in the chain preceding the AdvisoryBroker)
that could be creating and retaining objects related with these advisory
topics won't never be able to release them.
Perhaps this way to proceed could be related with the fix of AMQ-677.
Did I miss anything?
Regards.
