Threads stuck in "unknown" state with UIL2

[rsoto]

I am currently experiencing some problems when using UIL2 invocation layer. I have been seeing incorrect thread counts for some time (~ when I upgraded to 3.2.2 I think). If I look at the ServerInfo MBean and look at the thread dump, the count is nowhere near the number of threads the dump is reporting. I started up JBoss in debug mode and when I connect to it with a jdb session, I can see in the JBossMQ thread group there are many (a couple thousand) threads laying around that are reported to be in state "unkown". Where all threads are either in a "running" or "waiting" state, these threads in the "waiting" state do not appear in a thread dump as well. When I look at a stack trace for any of these threads I can see that they are instances of "SImpleTimerThread" instantiated from somepoint (can't remember exactly where) in the UIL2 layer. Has anyone seen this before? I am running in a pub/sub environment with ~350 topics created and up to 400 UIL2 connections and ~50 OIL connections. This did happen whether or not I was creating any OIL connections.

Thanks.

[rsoto]

One other note, this happens whether I use HyperSQL or MySQL for JMS persistence.

[adrian.brock]

This is the new scheduled delivery processing.
It instatiates an object of SimpleTimer per subscription
which extends java.lang.Thread

The thread isn't actually running so it is state "Unknown".
The JVM just counts the number of java.lang.Thread
objects rather than the real system threads.

Thanks for pointing me at this code. It is crying out
for a ThreadPool.

Regards,
Adrian

[rsoto]

Ok. Phew! I thought there might be some massive thread leak and I was starting to get nervous. Do these threads ever start? It also appears that the objects never get cleaned up, even after the connection has closed.


Thanks.
Ray.

[adrian.brock]

They are not part of the connection, they are part of the
queue/subscription.

They do start if you schedule a message for delivery.
Which is why I said it should use a thread pool
with one thread waking up when the next delivery is
required.

Regards,
Adrian

[danielsmolenaars]

Hi, I am having the same problem with Jboss 4.0.1, the msg is sent to the Queue, the msg is executed, but It create some kind of thread zombies even if the msg is processed with success.

And the threads never desapear until we reboot the server.

What should I do?

Thanks.