Privileges needed by pg_autovacuum?

I've password protected the 'postgres' account (to enable secure remote
access) and I don't want to store the password on the local file system.
I therefore want to create a separate account for use by pg_autovacuum
(locked down in pg_hba.conf and perhaps with a password).  What are the
minimum set of privileges needed by pg_autovacuum?  I've searched
extensively & can't find an answer.

--
Peter Fein                 pfein@pobox.com                 773-575-0694

Basically, if you're not a utopianist, you're a schmuck. -J. Feldman