[jboss-dev-forums] [Design of JCA on JBoss] - [JBAS-5095] Race condition between connection.close() and tr

[jesper.pedersen]

I have been looking at subject for both 5.0.CR2 and 4.2.4.GA.

As Adrian states there is a race condition between connection.close() and an asynchronous transaction  completion (e.g. transaction timeout) that can lead to a leaked connection permit with eventual pool exhaustion when using track-connection-by-tx (i.e. all local resources).

The fix (has he states) is to check that the number of handles are zero and the connection no longer is track-by-tx in an atomic way.

I have introduced a reentrant lock that is used when isManagedConnectionFree() is used in combination with returnManagedConnection(). The lock is defined as an instance variable in TxConnectionManager - and the code is guarded using the lock() / unlock() methods.

The overhead of the reentraant lock is minimal when operating with track-by-tx == false and the lock only comes into play in afterCompletion() when track-by-tx is true.

The patch have been attached to the JIRA issue for review.

Any feedback is welcomed !

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