[MichaelGG]

Excellent as usual. One question though. When refuting the rebuttal's claim:

>Moreover, if we test the same workload on a simple single instance InnoDB, we will get the same result.

He simply states that he tested it and it didn't happen, so it must be OK. But later on says the x=x+y form perhaps only accidentally works as "I suspect that this only passes because the window of concurrency for the read/write cycle is very short".

Why wouldn't this be true of the single-node scenario? Certainly things are faster on a single node, so unless Jepsen is pre-empting and delaying each thread-instruction combination, a test passing certainly isn't proof of it actually being OK, right? It's possible that the same workload on a heavily overloaded instance, might, somehow, exhibit the same behaviour, eh? I understand that the next sentence goes on to attribute it to a likely problems with Galera's locks. But the test alone shouldn't be conclusive evidence. Not trying to be pedantic or discuss what "proof" means just curious as to if I missed something.