As discussed with Sanne Grinovero it'd be nice to make the ObjectLoaderHelper in Hibernate Search a service which can be customized by integrators. We could then implement a custom implementation which does non-PK-based look-ups based on a new method on GridDialect. If a given store does not support this sort of look-up (Infinispan?) we could raise a clear exception stating that a mapping where the document id is not the PK is not supported on that store.