elle

It does indeed! This is a part of https://github.com/jepsen-io/elle, which infers totally-connected components of the transaction dependency graph. :-)

TIL (from this article) about "elle", which is part of the Jepsen project but can be used independent of Jepsen, and now I'm happy. https://github.com/jepsen-io/elle I'm writing a DB storage engine, and was despairing about how I was going to test Tx consistency for correctness, and kept coming back to Jepsen to find it was a 10,000lb entity that would require me to spend dozens of hours to get a handle on and had a lot of stuff I didn't need. But it looks like "elle" can be run entirely independent of Jepsen, fired up from my unit tests and fed a log and it will tell me how broken my code is. Nice.

Speaking very loosely, primitives on the JVM are values which are represented directly in memory, instead of as pointers to objects on the heap. Clojure (again, very loosely) generally treats everything as a pointer to a heap object. There is no specialized equivalent for, say, a vector of shorts, or a map where values are floats. The compiler can emit specialized function signatures for... IIRC longs and doubles, but other types (e.g. byte, float) aren't directly accessible--they go through widening conversion. It's also easy for the compiler to quietly fail to recognize it can preserve primitives in some kinds of loops, so you wind up with what Java calls "autoboxing": wrapping a primitive in a corresponding Object type. Here's a recent example of some code in a hot path inside Elle, one of Jepsen's safety checkers. It does a lot in pri

also, https://github.com/jepsen-io/elle

Reading through the source of Elle: > "I cannot begin to convey the confluence of despair and laughter which I encountered over the course of three hours attempting to debug this issue. We assert that all keys have the same type, and that at most one integer type exists. If you put a mix of, say, Ints and Longs into this checker, you WILL question your fundamental beliefs about computers" [1]. I feel like Jepsen/Elle is a great argument for Clojure, reading the source is actually kind of fun. Not what you'd expect for a project like this. [1]: https://github.com/jepsen-io/elle/blob/master/src/elle/txn.c...

Oh! I didn't expect this to show up here! Happy to answer questions, if folks have any. While this is on frontpage, I'd like to ask: if anyone has experience with machine proofs, I'd appreciate your help in completing a formal proof of Elle's correctness. I've been teaching myself Isabelle/HOL in an attempt to formalize the proof sketch, and I have encoded most of the formalism and properties I care about, but actually proving lemmata has been... frustrating. Like, I burned hours one one lemma because it hinged on showing \forall x :: Nat, x \in N. https://github.com/jepsen-io/elle/tree/master/proof If you'd like to work on this, my email is aphyr@jepsen.io!

Github code : https://github.com/jepsen-io/elle