[jboss-user] [JBoss Messaging] - Re: Resource GC problem

The following is a copy of the email I sent to our group earlier today. Kev ----------------------------------------------------------------------------- - The way the current codebase repeatedly creates connections - The way JBoss Remoting works One cause appears to be the timers used by remoting. From what I can see there are three in play - ConnectionValidator - BisocketServerInvoker$ControlMonitorTimerTask - LeasePinger$LeaseTimerTask Each one of these timers has indirect access to the majority of the heap. The big culprit in the timers appears to be LeasePinger$LeaseTimerTask. When connections are closed this task is cancelled but unfortunately cancelling j.u.TimerTask does *not* remove the task from the queue, all it does is mark it as cancelled. The consequence of this is that every instance referenced by the task *cannot* be garbage collected until the timer would normally fire (and the task is then removed from the queue). Referenced from each LeasePinger instance is a BisocketClientInvoker which contains a ClientSocketWrapper. Each ClientSocketWrapper references a Socket, a DataInputStream (containing BufferedInputStream) and a DataOutputStream (containing BufferedOutputStream). Each BIS/BOS contains a 64k array! In my tests these instances amount to a cumulative size of about 1/3 of the heap. Another cause appears to be the use of hash maps. There are numerous hashmaps referenced from BisocketServerInvoker and BisocketClientInvoker which do not appear to be garbage collected. One reason is the above timers but a second is that BisocketServerInvoker holds on to BisocketServerInvoker references in a static map called listenerIdToServerInvokerMap. This map currently contains an instance of BisocketServerInvoker for every iteration of the loop. This has all been discovered from examining profile information, not source code. It may be that this analysis is completely wrong and that examination of the source code will highlight other issues. Kev View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4026657#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...