For truly efficient clustering of extended persistence contexts in the context of Seam or EJB3, we need a way to propagate unflushed changesets. What we need is an SPI like this: Serializable changeset = session1.getChangeSet(); session2.applyChangeSet(changeset); where session2 is an empty session, or perhaps even a session with some of the same entities as session1. The only state that needs to be sent in the changeset is new entities, unflushed updates to entities and deletions of entities. Steve, WDYT?