I wonder how hard it would be to adapt eg: postgres to keep history around forever. There's temporal tables in ANSI SQL 2011, but I think the semantics are diff

I wonder how hard it would be to adapt eg: postgres to keep history around forever. There's temporal tables in ANSI SQL 2011, but I think the semantics are different (it's per table, I believe). As much as I like datomic, I'd prefer an implementation in a lower level language. However, I'm pretty sure there are alot of clojure experts out there pushing datomic to its limits.