> but it occurred to me that the rollback may not reset the auto-increment IDs in MySQL so those would just keep incrementing anyway. That’s got to be it. I’m using Postgres and yeah it looks like the auto-increment doesn’t reset, but the inserts are in fact rolled back.

Phew! I'm glad to hear that @ccann!

sorry for the false alarm, definitely a knowledge gap on my part

No worries. It definitely had me questioning whether there was a bug in clojure.java.jdbc in its transaction handling, since that's some gnarly -- and very imperative -- code that deals with mutable state.