Surprisingly, no it does not. Datomic has a more limited feature that lets you make an in-memory clone of the latest copy of the db for speculative writes, which might be useful for tests, but you can't take an arbitrary version of the db with as-of and use it as the basis for a new version on disk. See: https://blog.danieljanus.pl/2025/04/22/datomic-forking-the-p...

There's nothing technically that should prevent this if they are using HAMTs underneath, so I'm guessing they just didn't care about the feature. With HAMT, cloning any part of the data structure, no matter how nested, is just a pointer copy. This is more useful than you'd think but hardly any database makes it possible.