edit: the underlying connector might be a better idea to start with, as it'll need to expose the fields somehow before an ORM can take advantage of them.
EDIT: Seems like they have dropped support for postgres.
EDIT2: Yes, I did mean postgres-pr.
Specifically at any error handling, which I think would likely be here:
https://github.com/rails/rails/blob/master/activerecord/lib/...
