[xapata]

No, he's saying it's effectively CAP because the A downtime is so small.

It's one thing to do that for a key-value store. Entirely another to support joins on a globally distributed database. This ain't just one availability zone. Spanner is amazing.

It took them a few years to make it a service, but when they announced its use internally a few years ago, it seemed like the nail in the coffin for in-house database hosting.

[jhugg]

I understand what he's saying. It's marketing.

There's nothing wrong with saying it's CP, but since we control everything there's extremely rare P. Then he can show availability numbers (which he kinda does).

Saying it's "effectively CA" defeats the point of the CAP theorem, which says you have to make tradeoffs. See: https://codahale.com/you-cant-sacrifice-partition-tolerance/

[xapata]

> It's marketing.

No, it's engineering. It's the recognition that if periods of unavailability are too small and too rare to be noticed, then the system behavior is indistinguishable from an "available" system in the sense of the CAP theorem.

It's like the "Retina" display you're probably reading from. There are pixels, you just can't see them.