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> Imagine if you could just start an arbitrary computation and the system guarantees that it will run until completion and all the operations will be performed
by tomjakubowski 3y ago
> Imagine if you could just start an arbitrary computation and the system guarantees that it will run until completion and all the operations will be performed exactly once.
How is this guaranteed? Isn't exactly once delivery in a distributed system impossible?
- jiveturkey 3y agoIt does say, _Imagine_. Not sure what you're quoting, I don't see this text in TFA and your comment is not a child of another.
- tlarkworthy 3y agoExactly once processing is possible with idempotence keys over an at least once delivery system.
- mgdev 3y agoYou've just pushed the problem down to the system that checks idempotence keys.
- brodouevencode 3y agoIf you're referring to the CAP theorem, it needs some clarification: https://www.infoq.com/articles/cap-twelve-years-later-how-the-rules-have-changed/ https://www.infoq.com/articles/cap-twelve-years-later-how-th...
- hedora 3y agoIt's not impossible. You just pick CP from the CAP theorem (and give up availability). i.e., the message will be delivered exactly once if the system makes progress. If you want an existence proof, NFSv3 had this working back in the 1980's. I doubt it was the first.