Is it possible to handle financial transactions on eventually consistent datastores?
My hypothesis is "no", because any two parties (buyer and seller) may need to have balances updated in a single atomic transaction, and this tran saction must have ACID semantics. In short, the user-facing semantics are non-idempotent, so I cannot see a way to make this work.
Is it possible? If so, how? If not, is there a proof?