[Springframework-developer] Problems with Hibernate and Spring

[Stefan M. <s....@s2...>]

Hi,

I have encountered the following problems with Spring/Hibernate:

1. 
situation:
- there is a thread bound hibernate session.
- a method A is called and a transactionInterceptor begins a new Transaction
on the thread bound session.
- method A calls method B. The invocation is again intercepted by a
TransactionInterceptor which behavior is PROPAGATION_REQUIRED. The existing
transaction is reused. 
- An exception is thrown in the body of method B.
- The TransactionInterceptor on method B catches the exception and calls
sessionHolder.setRollbackOnly(). 
- The top-level TransactionInterceptor will find that
sessionholder.rollbackOnly=true and rollback the transaction.

problem:
sessionHolder.rollbackOnly is never reset although the transaction is over.
Thus the following transactions on this session will be rolled back as well.

2. 
situation:
- a transaction is begun.
- different objects are persisted or removed from the database.
- the transaction is rolled back.

Problem:
- The database operations are first put into hibernate's session cache. And
they won't be executed/removed until session.flush() or session.clear() are
called. The TransactionInterceptor only issues a rollback on the
Transaction. Therefore flushing the session after the transaction is over
will execute the database operations even though they should have been
rolled back.

I have fixed these issues by making changes to HibernateTransactionManager,
i.e. flushing the session and setting the sessionHolder.rollbackOnly to
false before rollback.

Changes to HibernateTransactionManager:

	protected void doRollback(DefaultTransactionStatus status) {
		HibernateTransactionObject txObject =
(HibernateTransactionObject) status.getTransaction();
		if (status.isDebug()) {
			logger.debug("Rolling back Hibernate transaction on
session [" +
	
txObject.getSessionHolder().getSession() + "]");
		}
		try {
			//unset rollbackOnly. 
			txObject.getSessionHolder().unsetRollbackOnly();
			try 
			{
				//flush before rollback to remove all
pending batch actions
				if (flushBeforeRollback)
txObject.getSessionHolder().getSession().flush();
			} 
			catch (HibernateException e) {
				logger.error("flushing session ["
+txObject.getSessionHolder().getSession() + "] before rollback failed");
			}
	
txObject.getSessionHolder().getTransaction().rollback();
		}
		catch (net.sf.hibernate.TransactionException ex) {
			throw new TransactionSystemException("Could not
rollback Hibernate transaction", ex);
		}
		catch (JDBCException ex) {
			// shouldn't really happen, as a rollback doesn't
cause a flush
			throw
convertJdbcAccessException(ex.getSQLException());
		}
		catch (HibernateException ex) {
			// shouldn't really happen, as a rollback doesn't
cause a flush
			throw convertHibernateAccessException(ex);
		}
	}

Changes to SessionHolder:

Added method sunsetRollbackOnly().



Is there another way?





--
Stefan Meyer