I'm pulling my hair out because people are using eventual consistency to mean "eventual consistency with a noticeable lag before the consistency is achieved", which bothers the pedant in me.
I mean, technically, strong consistency implies eventual consistency (with lag = 0). But everyone's equating eventual consistency with the noticeable lag itself, implying that EC per se is a bad thing.
For an analogy, it would be like if people were talking about how rectangular cakes suck, because <problems of unequal width vs length>, and thus they use square cakes, but ... square cakes are rectangular too.
(What's going on is that people use <larger set> to mean <larger set, excluding members that qualify for smaller set>. <larger set> = eventual consistency, rectangle; <smaller set> = strong consistency, square.)
Obviously, it's not a problem for communication because everyone implicitly understands what's going on and uses the words the same way, but I wish people spoke in terms of "has anyone actually seen a consistency lag?" rather than "has anyone actually seen eventual consistency?", since the latter is not the right way to frame it, and is actually a good thing to have, which happened both before and after this development.
Eventual consistency with zero lag is not strong consistency. Two simultaneous conflicting writes with eventual consistency will appear successful. Strong consistency guarantees that one of the writes will fail.
EDIT: I think the reason people care about the lag is specifically for this case; if you want to know if your eventually consistent write actually succeeded then you need to know how long to wait to check.
Well, in all the threads, they’re describing situations with lag. That is, they’re equating eventual consistently with the lag, and implying it’s therefore bad, when eventual consistency can include unnoticeably small lag.
And thus it’s the lag that they’re actually bothered by, not the EC per se. Hence my clawed out hair.
I mean, technically, strong consistency implies eventual consistency (with lag = 0). But everyone's equating eventual consistency with the noticeable lag itself, implying that EC per se is a bad thing.
For an analogy, it would be like if people were talking about how rectangular cakes suck, because <problems of unequal width vs length>, and thus they use square cakes, but ... square cakes are rectangular too.
(What's going on is that people use <larger set> to mean <larger set, excluding members that qualify for smaller set>. <larger set> = eventual consistency, rectangle; <smaller set> = strong consistency, square.)
Obviously, it's not a problem for communication because everyone implicitly understands what's going on and uses the words the same way, but I wish people spoke in terms of "has anyone actually seen a consistency lag?" rather than "has anyone actually seen eventual consistency?", since the latter is not the right way to frame it, and is actually a good thing to have, which happened both before and after this development.