> Does this mean that Spanner is a CA system as defined by CAP? The short answer is “no” technically, but “yes” in effect and its users can and do assume CA.

> Does this mean that Spanner is a CA system as defined by CAP? The short answer is “no” technically, but “yes” in effect and its users can and do assume CA. It's somewhat ironic that Brewer, the original author of the CAP theorem, is making this sort of marketing-led bending of the CAP theorem terminology. I think what he really should be saying is something in more nuanced language like this: https://martin.kleppmann.com/2015/05/11/please-stop-calling-databases-cp-or-ap.html https://martin.kleppmann.com/2015/05/11/please-stop-calling-... But perhaps Google's marketing department needed something in the more popular "CP or AP?" terminology. I don't see what would be wrong with "CP with extremely high availability" though. It's certainly wacky to be claiming that a system is "CA", since as the post admits it's technically false; to me this makes it clear that CP vs. AP (vs. CA now?) does not convey enough information. I'd prefer "a linearizably-consistent data store, with ACID semantics, with a 99.999% uptime SLA". Not as snappy as "CA" (I will never have a career in marketing I suppose), but it makes the technical claims more clear.