Hi,
I have a small program which is persisting an object in database then delete it just after (ok, it makes no
sense but it's just for testing purpose!).
Here is the code :

public void run() {
// create alarm
Alarm alarm = new Alarm();
alarm.setName("new");
Alarm created = service.create(null, null, alarm);

// get primary key of created alarm
Long pk = created.getOid();

// delete alarm
service.delete(pk);
} catch (Exception e) { ...}
}

To simulate several clients, this code is executed in a thread.
My problem is that if I execute this program with more than 3 threads, I get an hibernate
LockAcquisitionException caused by an oracle exception : ORA-00060: deadlock detected while waiting for resource.

I don't understand why I have this problem with a so simple program.

Any ideas?


Hibernate version: 3.2.0

Full stack trace of any exception that occurs:
org.hibernate.exception.LockAcquisitionException: could not delete: [net.ejb.model.alarm.Alarm#40726]
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:87)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:2491)
at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:2647)
at org.hibernate.action.EntityDeleteAction.execute(EntityDeleteAction.java:74)
at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:248)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:232)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:144)
at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:298)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000)
at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:338)
at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:106)
Caused by: java.sql.SQLException: ORA-00060: deadlock detected while waiting for resource

at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:331)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:288)
at oracle.jdbc.driver.T4C8Oall.receive(T4C8Oall.java:743)
at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:216)
at oracle.jdbc.driver.T4CPreparedStatement.executeForRows(T4CPreparedStatement.java:955)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1168)
at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3316)
at oracle.jdbc.driver.OraclePreparedStatement.executeUpdate(OraclePreparedStatement.java:3400)
at com.p6spy.engine.logging.P6LogPreparedStatement.executeUpdate(P6LogPreparedStatement.java:183)
at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:2473)

Name and version of the database you are using:Oracle 10

From your code it is not clear, if you commit transactions or not. If your delete stays uncommited, you may receive a lock.

I have found the problem.
It comes from an oracle parameter called initrans which must be increased.