Skip to main content
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [List Home]
Re: [eclipselink-users] EclipseLink lockup in exclusive isolated session mode 
I can't reproduce running out of connections:

persistence.xml:
<persistence xmlns="http://java.sun.com/xml/ns/persistence"; xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; xsi:schemaLocation="http://java.sun.com/xml/ns/persistence persistence_1_0.xsd" version="1.0"> <persistence-unit name="customfeatures" transaction-type="RESOURCE_LOCAL"> 

<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>

<class>org.eclipse.persistence.testing.models.jpa.customfeatures.Employee</class>
        <properties>
<property name="eclipselink.session.customizer" value="org.eclipse.persistence.testing.models.jpa.customfeatures.Customizer"/> <property name="eclipselink.jdbc.exclusive-connection.mode" value="Always"/> 
        </properties>
    </persistence-unit>

</persistence>
The testing framework I am using passes user/password/url to createEntityManagerFactory method. 
I am creating a data source in customizer:
public class Customizer implements SessionCustomizer {
    public void customize(Session session) throws SQLException {
        OracleDataSource ds = new OracleDataSource();
        ds.setURL(session.getLogin().getConnectionString());
        session.getLogin().setConnector(new JNDIConnector(ds));
        session.getLogin().useExternalConnectionPooling();
    }
}
The test runs forever using the same connection all the time no matter is it find, query or native query. 
    public void testExclusiveSessionRunOutOfConnections() {
        EntityManager em = createEntityManager("customfeatures");
        boolean loop = true;
        while(loop) {
            beginTransaction(em);
//            Employee emp = em.find(Employee.class, 1);
// List<Employee> employees = em.createQuery("SELECT OBJECT(e) FROM Employee e").getResultList(); List names = em.createNativeQuery("SELECT NAME FROM CUSTOM_FEATURE_EMPLOYEE").getResultList(); 
            commitTransaction(em);
        }
    }

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

On 12/9/2010 9:27 AM, patric@xxxxxxxxxxx wrote:

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


_______________________________________________
eclipselink-users mailing list
eclipselink-users@xxxxxxxxxxx
https://dev.eclipse.org/mailman/listinfo/eclipselink-users

Back to the top