Adding a RETURNING clause does nothing with respect to maintaining consistency between the persistent store and the in-memory view of the database. It is entirely possible and likely that changes to the persistent store will occur independently of the one bitty program that wants to use the RETURNING clause. Reliance upon RETURNING for this purpose pre-supposes that the database is SINGLE-USER. Unless one is taking precautions to ensure that the datastore is in fact SINGLE-USER and cannot be modified by anyone else, then using RETURNING to maintain consistency is ill-conceived. Rather than wasting time on ill-conceived endeavours, I would suggest that it would be far more productive to take a more holistic and realistic view which is not dependent on a state of fact that does not exist.