hi Manuel,
on the face of it - this does look like an issue was introduced by
the change in trunk you mentioned. I think the code was changed to
help some concurrency issues. However, the broker has changed
considerably since then, so I'm not sure it still applies. The best
thing to do would be to apply your patch + rollback the change in
AbstractBroker you highlighted, and see if anything breaks ;)
cheers,
Rob
On Jul 9, 2007, at 1:57 PM, Manuel Teira wrote:
And even worse, creating the destination in this way (inside the
TopicRegion) is not going to make the RegionBroker aware of it.
Since the AdvisoryBroker is relaying in the broker chain to try to
delete the consumer and producer advisory topics when a destination
is deleted, how and when are they supposed to be deleted in the
trunk code?
Regards.
Manuel Teira escribió:
Hi again.
I'm afraid that the lookup code in AbstractRegion has being
changed in the trunk (I was looking at 4.1 branch). Basically,
instead of calling context.getBroker().addDestination
(context,destination) to create the new destination, addDestination
(context, destination) is used. This way, the advisory topic won't
be created from top, but what happens with the advise in the code?
if(autoCreateDestinations){
// Try to auto create the destination... re-
invoke broker from the
// top so that the proper security checks are
performed.
try {
dest = addDestination(context, destination);
//context.getBroker().addDestination
(context,destination);
}
I suppose that the assumption is no longer true.
Also, the way to change this code (only commenting out the old
one) makes me think about a not too mature change?
If you can verify that this is the right way to proceed,I will
like to prepare a patch against 4.1 branch.
Best regards.
Manuel Teira escribió:
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.
Rob Davies
'Go further faster with Apache Camel!'
http://rajdavies.blogspot.com/
