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[eclipselink-users] EclipseLink lockup in exclusive isolated session mode

Hello,

I am experiencing a critical issue when using the exclusive isolated session mode which results in a lockup during a database call.

To reproduce it, do the following:

1. Enable exclusive isolated session mode (property eclipselink.jdbc.exclusive-connection.mode = Always) and use the external connection pool mode
2. Use a non-JTA Datasource
3. Begin EntityManager transaction
4. Do a JPA Operation (e.g. find())
5. Commit the EntityManager transaction
6. Repeat steps 3-5 several times (ca. 50)
=> database call will lock.


I investigated this issue and it seems that a EntityManager transaction commit will not release the connection hold by the exclusive isolated client session (which is fine and expected).
But, due to the "resetted" transaction it will acquire a new one than re-using the acquired one.


After some iterations, maxNumberOfNonPooledConnections will be exceeded, which will end up that the ServerSession will wait forever for obtaining a new connection in the wait() call.

Here's the stacktrace for the issue:
Thread [Thread-3] (Suspended)
waiting for: ServerSession (id=313)
Object.wait(long) line: not available [native method]
ServerSession(Object).wait() line: 474
ServerSession.acquireClientConnection(ClientSession) line: 268
ExclusiveIsolatedClientSession(ClientSession).basicBeginTransaction() line: 123
ExclusiveIsolatedClientSession(AbstractSession).beginTransaction() line: 552
RepeatableWriteUnitOfWork(UnitOfWorkImpl).beginTransaction() line: 509
RepeatableWriteUnitOfWork(UnitOfWorkImpl).beginEarlyTransaction() line: 499
EJBQueryImpl.executeReadQuery() line: 383
EJBQueryImpl.getResultList() line: 568
...


And I've got another question: will EntityManager.close() release/close the acquired connection in the exclusive isolated mode?


I really appreciate your help.

Best regards,
Patric