Michiel Lange <michiel(at)minas(dot)demon(dot)nl> writes:
> It is, somehow, not possible to connect as a user which name is completely
> numeric.
I muttered "nonsense!" to myself, but darned if you're not right:
regression=# create user "12345";
CREATE USER
regression=# \q
$ psql -U 12345 regression
psql: FATAL: SET SESSION AUTHORIZATION: permission denied
Will look into it.
regards, tom lane