[jboss-dev-forums] [Design of EJB 3.0] - Unnecessary read before update with merge()

[markvl2]

Hope I'm not posting this to the wrong forum. I raised this first on the EJB3 and Hibernate user forums but have come to the conclusion it is a design / implementation issue with EJB3/Hibernate.

I have a simple case of an entity which is read in one thread, then updated in another thread using merge().

The Hibernate merge() code always reads the original value of a detached entity. From DefaultMergeEventListener.entityIsDetached():


  | 		//we must clone embedded composite identifiers, or 
  | 		//we will get back the same instance that we pass in
  | 		final Serializable clonedIdentifier = (Serializable) persister.getIdentifierType()
  | 				.deepCopy( id, source.getEntityMode(), source.getFactory() );
  | 		final Object result = source.get(entityName, clonedIdentifier);
  | 

It should be possible to update the entity without the original value of the entity being read from the DB. This is causing an unncecessary call to the DB.
 


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