All,
I have an application that creates a new session and attempts to achieve a pessimistic lock one a SINGLE item in the DB. Sometimes when I do this, I get the following exception:
Code:
2006-05-10 00:00:16,051 [http-0.0.0.0-20080-105] ERROR exception:org.hibernate.exception.GenericJDBCException: could not load an entity: [com.real.mediaengine.admin.data.HManager#47850]
at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:91)
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:79)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
at org.hibernate.loader.Loader.loadEntity(Loader.java:1799)
at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:93)
at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:81)
at org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:2730)
at org.hibernate.event.def.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:365)
at org.hibernate.event.def.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:346)
at org.hibernate.event.def.DefaultLoadEventListener.load(DefaultLoadEventListener.java:123)
at org.hibernate.event.def.DefaultLoadEventListener.lockAndLoad(DefaultLoadEventListener.java:272)
at org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:90)
at org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:891)
at org.hibernate.impl.SessionImpl.load(SessionImpl.java:872)
at org.hibernate.impl.SessionImpl.load(SessionImpl.java:867)
at com.real.mediaengine.admin.ejb.commandHandlers.GetManagerUpdatesHandler.handleTaskAssignmentWork(GetManagerUpdatesHandler.java:154)
at com.real.mediaengine.admin.ejb.commandHandlers.GetManagerUpdatesHandler.perform(GetManagerUpdatesHandler.java:79)
at com.real.mediaengine.admin.ejb.commandHandlers.AdminCommandHandler.performCommand(AdminCommandHandler.java:52)
at com.real.mediaengine.admin.ejb.MediaEngineAdminBeanImpl.performManagerAction(MediaEngineAdminBeanImpl.java:369)
at sun.reflect.GeneratedMethodAccessor117.invoke(Unknown Source)
Caused by: java.sql.SQLException: ORA-00060: deadlock detected while waiting for resource
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)
at oracle.jdbc.ttc7.TTIoer.processError(TTIoer.java:289)
at oracle.jdbc.ttc7.Oall7.receive(Oall7.java:582)
at oracle.jdbc.ttc7.TTC7Protocol.doOall7(TTC7Protocol.java:1986)
at oracle.jdbc.ttc7.TTC7Protocol.parseExecuteDescribe(TTC7Protocol.java:880)
at oracle.jdbc.driver.OracleStatement.doExecuteQuery(OracleStatement.java:2516)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:2850)
at oracle.jdbc.driver.OraclePreparedStatement.executeUpdate(OraclePreparedStatement.java:609)
at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:537)
at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:139)
at org.hibernate.loader.Loader.getResultSet(Loader.java:1669)
at org.hibernate.loader.Loader.doQuery(Loader.java:662)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:224)
at org.hibernate.loader.Loader.loadEntity(Loader.java:1785)
... 72 more
Please notice, in particular, the last few lines:Code:
Caused by: java.sql.SQLException: ORA-00060: deadlock detected while waiting for resource
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)
at oracle.jdbc.ttc7.TTIoer.processError(TTIoer.java:289)
at oracle.jdbc.ttc7.Oall7.receive(Oall7.java:582)
at oracle.jdbc.ttc7.TTC7Protocol.doOall7(TTC7Protocol.java:1986)
at oracle.jdbc.ttc7.TTC7Protocol.parseExecuteDescribe(TTC7Protocol.java:880)
at oracle.jdbc.driver.OracleStatement.doExecuteQuery(OracleStatement.java:2516)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:2850)
at oracle.jdbc.driver.OraclePreparedStatement.executeUpdate(OraclePreparedStatement.java:609)
at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:537)
at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:139)
at org.hibernate.loader.Loader.getResultSet(Loader.java:1669)
at org.hibernate.loader.Loader.doQuery(Loader.java:662)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:224)
at org.hibernate.loader.Loader.loadEntity(Loader.java:1785)
... 72 more
This happens when I execute the following lines of code (this doesn't happen all the time - it happens rarely - but it happens - the exception is being thrown on the call to session.load():Code:
Session session = HibernateUtil.getSession();
Transaction transaction = session.beginTransaction();
HManager manager = (HManager)session.load(HManager.class, managerId, LockMode.UPGRADE);
Here is my HibernateUtil class (very short):Code:
package com.goober.mediaengine.admin.common;
import org.hibernate.*;
import org.hibernate.cfg.*;
public class HibernateUtil {
private static final SessionFactory sessionFactory;
static {
try {
Configuration cfg = new Configuration();
sessionFactory = cfg.configure().buildSessionFactory();
// SessionFactory is now in JNDI, see hibernate.cfg.xml
} catch (Throwable ex) {
// Make sure you log the exception, as it might be swallowed
System.err.println("Initial SessionFactory creation failed." + ex);
ex.printStackTrace(System.out);
throw new ExceptionInInitializerError(ex);
}
}
public static Session getSession() throws HibernateException {
return sessionFactory.openSession();
}
}
Basically, I'm creating a new session, and trying to obtain a pessimistic lock on a particular item. I know there are other threads out there that are trying to get a pessimistic lock on the same item - but since my session has no locks (yet), I don't see how I could possibly (even theoretically) get deadlock...
I am using hibernate 3.1.2 with an oracle database on the backend. I'm running under JBoss and using stateless session beans.
Is it possible that the session object that I "create" is being recycled by hibernate and not being "cleaned up" properly?
Any light you can shed would be extremely helpful.
Thanks,
-john
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