This is framed as a new characterization of the properties of database servers, but isn't just about whether the client waits for acknowledgment from the cluster?<p>It seems completely unrelated to the server's consensus algorithm. Any client for any of those systems can proceed before the transaction is committed, it is faster but means that your transaction might disappear if the wrong node crashes.<p>How does the author end up with an empty column for "PC/EL" in their table and not realize that "choosing [low] latency" (by not waiting for acknowledgment) is no longer guaranteed consistent?