I don't understand how this can be generalized to non-deterministic systems. First off, the definition of non-deterministic is unclear to me. His definition of deterministic seems wrong, as he's using a set of requests. Sets are unordered, so this would imply that the order in which requests execute is irrelevant - which is true for commutative operations, but Calvin doesn't seem to be limited to those.

Assuming that "deterministic" should be defined on lists of inputs, then I don't understand how the approach can be applied to nondeterministic databases. The crux seems of the approach seems to be in consistent distributed reads (which you can get by globally ordering transactions and MVCC). But for fault-tolerance, these must also be repeatable, and I don't see how to make them repeatable if the state of replicas in a shard is allowed to diverge.