Our solution was to write our own ORM-like system that “remembers” which entities you’ve loaded within the context of the transaction, and then will fetch the relation for all of them. So if you access a1.b then it will also fetch a2.b and cache it if you loaded a2 within that same transaction. The call to a2.b will then resolve instantly. So instead of n queries with n being the number of entities loaded in lazy loading, you’re doing n queries with n being the number of relations touched.

The one bad failure case is if you update entities one-by-one but also accessing their relations in a loop since you invalidate the cache for that entity type on every write.