Re:Spanner, TrueTime and the CAP Theorem [pdf]
by solipsism on Thursday December 14, 2017 @05:07PM
(#15927615)
Pardon the eyeroll, but that's incredibly pedantic. Brewer is not being disingenuous here, he's being forthright. Spanner is a product. "Effectively CA" is what customers care about. The fact that it's "technically not CA" is only important academically, and for the very small subset of customers for whom even the very tiny chance of loss of availability is problematic.
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Re:Spanner, TrueTime and the CAP Theorem [pdf]
by theptip on Thursday December 14, 2017 @06:41PM
(#15928446)
The point that the GP is making is there is no such thing as "effectively CA". CA is a specific academic term with a specific meaning; there's no reason to introduce it into the conversation if you're not going to follow that meaning.
By all means call this system a "ultra-high availability strongly consistent datastore", but it's still not CA.
(It's all the more disappointing that it's Brewer himself, the original author of the CAP theorem, that's engaging in this hand-waving).
Re:Spanner, TrueTime and the CAP Theorem [pdf]
by manigandham on Thursday December 14, 2017 @06:13PM
(#15928196)
Accuracy is not pedantic, especially when claiming something which is impossible. If customers don't care about availability than they also don't care about the difference between CP or CA, so why not just stick to CP which is real?
Perhaps disingenuous was too harsh, but my issue is that it took plenty of time for CAP to be well-understood and this marketing material does more harm than good by creating confusion. There are better ways of product marketing that don't try to fudge descriptions with technicalities.