JPA NamedQuery does not pick up changes to modified Entity

Question

I have a method that retrieves Entities using a NamedQuery. I update a value of each entity and then run another named query (in the same method and Transaction) filtering by the old value and it returns the same Entities as if I had not changed them.

I understand that the EntityManager needs to be flushed and also that it should happen automatically but that doesn't make any difference.

I enabled hibernate SQL logging and can see that the Entities are not updated when I call flush but when the container transaction commits.

EntityManager entityManager = getPrimaryEntityManager();
MyEntity myEntity = entityManager.find(MyEntityImpl.class, allocationId);
myEntity.setStateId(State.ACTIVE);
// Flush the entity manager to pick up any changes to entity states before we run this query.
entityManager.flush();
Query countQuery = entityManager
     .createNamedQuery("MyEntity.getCountByState");
// we're telling the persistence provider that we want the query to do automatic flushing before this
// particular query is executed.
countQuery.setParameter("stateId", State.CHECKING);
Long count = (Long) countQuery.getSingleResult();
// Count should be zero but isn't. It doesn't see my change above

Answer 1

To be honest I'm not that familiar with JPA, but I ran into similar problems with Hiberate's session manager. My fix was to manually remove the specified object from Hibernate's session before querying on it again so it's forced to do a lookup from the database and doesn't get the object from cache. You might try doing the same with JPA's EntityManager.