Also If my understanding is anywhere near correct, it's a mix of Paxos and a bit of a proxying sequencer (which may be implemented in a physical switch) and all replicas & master need to be on the same switch/subnet...
Going to read the paper now -- anyone have a better understanding of the tech they could share? Excited but still a bit skeptical
If you use a NoSQL database, the relations do not disappear. You just have to implement your joins in a higher layer. NoPaxos pushes some parts of Paxos into lower levels, namely the OUM primitive of the network.
Relations ~= Consensus (traditional full-featured Paxos)
To use your sentence
If you use NOPaxos, the consensus doesn't disappear. You just have to perform it whenever your sequencer, or replica-leader becomes unreachable/fails.
The "OUM primitive" addition isn't much more than two monotonically increasing integers (session and order-number) which depend on a central (bottleneck) sequencer... NoSQL moved the responsibility for relation-management up, NoPaxos is moving the responsibility for consensus down/to the worst case... My point was that neither are fundamentally different from the "X" after the "NO"...
SQL as language can have it issues but the relational model is far easier and more flexible than people assume.
The paper seemed to be missing an exploration of worst-case scenarios and equivalencies though, but I guess I guess worst case is paxos speed (consistently failing sequencer, or a leading replica that receives one messages then is unreachable, bad quorums, etc)