When using a javax.sql.DataSource via @DataSourceDefinition to create the JTA datasource for a persistence unit, transactional EJB business methods run without transactions. No warning or error is emitted.

Business method calls annotated @TransactionAttribute(TransactionAttributeType.REQUIRED) receive an EntityManager that is in autocommit mode, ie is not in a transaction.

This violates the EJB3 spec and is a nasty problem.

I discovered this when testing some code against PostgreSQL that uses deferred constraints to create two interdependent database objects; record A must have at least one record B referencing it, but record B also has a foreign key reference to record A. This can be satisfied only with deferred constraints, and works fine in SQL-level testing. When testing with Arquillian at the JBoss AS 7 / Hibernate / JPA level, though, it was breaking.

Further investigation showed that the entity manager was in autocommit despite the method being transactional, as demonstrated by a test that tries to create and fetch from a cursor.

I've now verified that the issue exists when using PostgreSQL or H2 as the database, so it's not specific to PostgreSQL. I've attached test cases for both databases.

JBoss AS 7 clearly has some validation and checking to do because it must not allow an autocommit entity manager to be injected for transactional business methods. That's a really critical error, as it effectively means that transaction isolation is always at DIRTY_READ (which most DBs don't even support) rather than the requested level, and it's impossible to roll back work!

As a workaround, it should be possible to deploy an archive with an embedded jboss-ds.xml instead of using @DataSourceDefinition . I haven't tested this - struggling to find documentation on in-archive deployment of jboss-ds.xml or equivalent jboss-specific descriptor like a datasource definition for jboss-web.xml .

Using the jboss admin cli, or deploying a jboss datasource definition xml file to the deployments folder separately to the program archive, isn't subject to the problem. That's a PITA when unit testing, though.