Maybe when you first start or access a new piece of data for the first time you maybe get a hiccup (maybe not - always profile to figure out how your specific application performs). If hiccups like that actually manifest, a nice way to solve that would be to attach the on-disk DB to the in-memory one, copy everything over (and maybe detach). If that DB is ever mutable at runtime, just copy the changes back in a background transaction to the on-disk DB (in this case I wouldn’t detach probably). This way you still get the persistence of the disk with the performance of RAM.
