1. Customer places an order.
2. SYN: Can I charge $30?
3. SYN/ACK: Yes.
4. ACK + SYN: Do it.
5. SYN/ACK: I am gonna do it.
6. ACK: I see that you're gonna do it.
"If that was their model, then at no point does a communication failure cause a charge to be in an ambiguous state. If I never get the message in #5, the customer is not charged. If I get the message in #5 and my response in #6 is not received, the customer is not charged."
Er.....that doesn't appear to solve anything, instead it just pushes the error state down a level; there's still an ambiguous state where #6 is sent and not received.
The client thinks the charge is going to take place, and so thinks the client will be charged, but the bank never gets #6 and so never makes the charge, aka distributed atomic operations are hard.
Er.....that doesn't appear to solve anything, instead it just pushes the error state down a level; there's still an ambiguous state where #6 is sent and not received.
The client thinks the charge is going to take place, and so thinks the client will be charged, but the bank never gets #6 and so never makes the charge, aka distributed atomic operations are hard.