created AMQ-1852 for this
On 10 Jul 2008, at 07:25, David Sitsky wrote:
Hi,
In my application, occasionally, my consumers mis-behave and can
consume a very large amount of memory. I have found that
occasionally, the consumer's associated TcpTransport thread can be
hit with an OutOfMemoryException as a result - for example, when
processing an incoming message.
What I found was the TcpTransport thread just dumped the
OutOfMemoryError to stderr and exited without notifying any of its
transport listeners.
It seems to me TcpTransport should catch Throwable (like it does
with IOException), and indicate to the listeners that the transport
is going down. We often catch Throwable in other parts of the code,
so it seems appropriate we do the same here.
Without this change, I found my consumer, which recovers from its
OutOfMemoryError, gets stuck since its transport thread has died,
for example, it calls session.commit() and never returns:
at sun.misc.Unsafe.park(Native Method)
- waiting on java.util.concurrent.locks.AbstractQueuedSynchronizer
[EMAIL PROTECTED]
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:158)
at java.util.concurrent.locks.AbstractQueuedSynchronizer
$ConditionObject.await(AbstractQueuedSynchronizer.java:1925)
at
java.util.concurrent.ArrayBlockingQueue.take(ArrayBlockingQueue.java:
317)
at
org
.apache
.activemq.transport.FutureResponse.getResult(FutureResponse.java:40)
at
org
.apache
.activemq
.transport.ResponseCorrelator.request(ResponseCorrelator.java:76)
at
org
.apache
.activemq.ActiveMQConnection.syncSendPacket(ActiveMQConnection.java:
1175)
at
org
.apache.activemq.TransactionContext.commit(TransactionContext.java:
259)
at org.apache.activemq.ActiveMQSession.commit(ActiveMQSession.java:
494)
Here is my proposed patch. Incidentally,
stoppedLatch.get().countDown(); only needs to be in the finally
block. In the current code, if an IOException is thrown, this
statement is executed twice.
Index: activemq-core/src/main/java/org/apache/activemq/transport/tcp/
TcpTransport.java
===================================================================
--- activemq-core/src/main/java/org/apache/activemq/transport/tcp/
TcpTransport.java (revision 675380)
+++ activemq-core/src/main/java/org/apache/activemq/transport/tcp/
TcpTransport.java (working copy)
@@ -183,8 +183,13 @@
doRun();
}
} catch (IOException e) {
- stoppedLatch.get().countDown();
onException(e);
+ } catch (Throwable t) {
+ // Make sure drastic conditions, such as
OutOfMemoryError are still
+ // reported to the transport's onException() listeners.
+ IOException e = new IOException("Unexpected exception
occurred");
+ e.initCause(t);
+ onException(e);
} finally {
stoppedLatch.get().countDown();
}
--
Cheers,
David
Nuix Pty Ltd
Suite 79, 89 Jones St, Ultimo NSW 2007, Australia Ph: +61 2 9280
0699
Web: http://www.nuix.com Fax: +61 2 9212
6902
