They use TLA+ with TLC which model checks the write ahead log (a component of the system). But that only models the WAL protocol, not the actual Rust code and not the other 99% of the system.
Any formal verification is of course awesome to see though.
My totally uneducated guess is that they leak exaggerated numbers on purpose to make the real numbers look less bad in comparison. The idea being that a few days before the official news everyone is talking about a potential 30 or 40K people layoff. Then, when the official news come out and state that they are laying off 14K people, it sounds less dramatic (in relative terms). This makes people (who are not affected by this) to feel like the news were overblown and are not as significant.
Obviously not. Suppose the input to my function is a 64-bit integer. My test cannot possibly try every possible 64-bit integer. It would take years for such a test to finish.
This is why tools like formal verification and symbolic analyses can help you establish that for all possible integers X, your function does the right thing (for some definition of “right”). You get this assurance without having to actually enumerate all X.
Very inefficient. Like wildly so. Specifically if you have a very small database and you preprocess it with their techniques, the resulting database is petabytes in size. But the results are very beautiful.
There are no obvious ways to improve on this work, so it is not a matter of engineering. We really do need another breakthrough result to get us closer to practicality.
They use TLA+ with TLC which model checks the write ahead log (a component of the system). But that only models the WAL protocol, not the actual Rust code and not the other 99% of the system.
Any formal verification is of course awesome to see though.