Gino Bustelo created UIMA-2401:
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Summary: BaseUIMAAsynchronousEngine_impl does not protect access
to SharedConnection in a multi-instance, multi-threaded scenario. Possible
javax.jms.IllegalStateException.
Key: UIMA-2401
URL: https://issues.apache.org/jira/browse/UIMA-2401
Project: UIMA
Issue Type: Bug
Components: Async Scaleout
Affects Versions: 2.3.1AS
Environment: RedHat Enterprise Linux 6.0, Mac OSX Lion 10.7.3
Reporter: Gino Bustelo
We see this problem sporadically when running one instance of
BaseUIMAAsynchronousEngine_impl per Thread. This means that each request Thread
will instantiate its own instance of BaseUIMAAsynchronousEngine_impl to submit
a CAS async. We have noticed in our logs the following exception:
org.apache.uima.adapter.jms.client.BaseUIMAAsynchronousEngine_impl WARN
2012-05-04 00:10:46,710 [BaseUIMAAsynchronousEngine_impl.803] - Top Level
Controller Initialization Exception.
javax.jms.IllegalStateException: The Session is closed
at
org.apache.activemq.ActiveMQSession.checkClosed(ActiveMQSession.java:722)
at
org.apache.activemq.ActiveMQSession.createConsumer(ActiveMQSession.java:1101)
at
org.apache.activemq.ActiveMQSession.createConsumer(ActiveMQSession.java:1060)
at
org.apache.activemq.ActiveMQSession.createConsumer(ActiveMQSession.java:973)
at
org.apache.activemq.ActiveMQSession.createConsumer(ActiveMQSession.java:946)
at
org.apache.uima.adapter.jms.client.BaseUIMAAsynchronousEngine_impl.initializeConsumer(BaseUIMAAsynchronousEngine_impl.java:523)
at
org.apache.uima.adapter.jms.client.BaseUIMAAsynchronousEngine_impl.initialize(BaseUIMAAsynchronousEngine_impl.java:687)
Under further inspection, it seems that the
BaseUIMAAsynchronousEngine_impl.initialize does not properly protects the
access to the SharedConnection object. Given the following scenario:
Thread 1 is in the middle of a call to UimaAsynchronousEngine.initialize.
Thread 2 is finishing up and calling UimaAsynchronousEngine.stop.
Thread 1 can be schedule out just before trying to create a Consumer
(BaseUIMAAsynchronousEngine_impl.java:523). Thread 2 will call stop() and due
to client count, cause the Connection to get closed. When Thread 1 comes back,
the Connection and Session instances that it has reference to are now invalid.
I've attached a test case that forces the exception to prove that there is no
proper mutex around access to the SharedConnection between initialize and stop.
I believe that the code in question is in
BaseUIMAAsynchronousEngine_impl.initialize between lines 682 and 700.
createSharedConnection(brokerURI);
synchronized (connectionMux) {
// Reuse existing JMS connection if available
if (sharedConnection != null) {
initializeProducer(brokerURI, endpoint,
sharedConnection.getConnection());
initializeConsumer(brokerURI, sharedConnection.getConnection());
} else {
initializeProducer(brokerURI, endpoint);
initializeConsumer(brokerURI);
}
// Increment number of client instances. SharedConnection object is a
static
// and is used to share a single JMS connection. The connection is
closed
// when the last client finishes processing and calls stop().
if (sharedConnection != null) {
sharedConnection.registerClient(this);
}
}
That entire block should be protected with the sharedConnectionSemaphore.
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