Maybe one of the reasons why hosted postgres often disallows extensions is due to security concerns from loading arbitrary machine code on a shared host. I wonder if pgrx changes the calculus here.

From the same org as pgrx is https://github.com/pgcentralfoundation/plrust, which _is_ supported on RDS (but not Aurora).

Since it's a procedural language, you can't do things like create a new index implementation or something else super low level. But there's still a lot you _can_ do. Like implement a custom comparator for a custom type and then use that type in a btree index.

Indeed, that's a much better formulation.