PostgreSQL's vacuumdb fails to allocate memory for non-root users

[Sven Willenberger]

FreeBSD 5.4-Release
PostgreSQL 8.0.3

I noticed that the nightly cron consisting of a vacuumdb was failing due
to "unable to allocate memory". I do have maintenance_mem set at 512MB,
and the /boot/loader.conf file sets the max datasize to 1GB (verified by
limit). The odd thing is that if I run the command (either vacuumdb from
the command line or vacuum verbose analyze from a psql session) as the
Unix user root (and any psql superuser) the vacuum runs fine. It is when
the unix user is non-root (e.g. su -l pgsql -c "vacuumdb -a -z") that
this memory error occurs. All users use the "default" class for
login.conf purposes which has not been modified from its installed
settings. Any ideas on how to a) troubleshoot this or b) fix this (if it
is something obvious that I just cannot see).

Thanks,

Sven