Jim Nasby <jnasby(at)pervasive(dot)com> writes:
> The problem with that is unless I missed a change in 8.1, autovac
> knows absolutely nothing about when manual vacuums have been run.
It knows perfectly well about full-database vacuums (because those
set pg_database.datvacuumxid), and by the end of the week or so it'll
know about single-table vacuums too:
http://archives.postgresql.org/pgsql-patches/2006-04/msg00009.php
regards, tom lane