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Comment by elvinyung | Hacker News Reader

Jepsen goes into detail about general CRDTs here: https://aphyr.com/posts/285-jepsen-riak

Yes, but devil's in the details. The fact CRDTs are provably able to have specific consistency guarantees doesn't mean a particular implementation does it correctly in all contexts. Without testing, "We built this (city) on CRDTs" isn't very useful.

Sure. My point is that it's a rough idea of what you could expect.

If you look at the Jepsen posts for Cassandra and Riak, for example, you can see that the general characteristics are fairly similar.

What's nice about building databases on compositions of CRDTs is that if you can validate the individual CRDTs via automated testing, you have a very high degree of confidence the composition of those CRDTs will do something similar.

No one's arguing that a Jepsen test shouldn't be done. Just that it'll probably be very different in character from more invented industry technology.

Yes; if you can prove a system was built atop an academically sound paradigm, it's more likely to adhere to the guarantees that paradigm is intended to provide than a system built atop an unproven paradigm. Kinda goes without saying, though. :P

Unsnarkily, I agree that implementation and composition of CRDTs is comparatively straightforward compared with other approaches people have taken. But if correct behavior is a requirement, full testing is too, regardless of how easy it -should- be in theory.

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