Re: PostgreSQL's vacuumdb fails to allocate memory for

On Wed, 2005-06-29 at 09:43 -0400, Douglas McNaught wrote:
> Sven Willenberger <sven(at)dmv(dot)com> writes:
>
> > 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).
>
> Is the out-of-memory condition occurring on the server or client side?
> Is there anything in the Postgres logs?

In this case they are one and the same machine ... i.e whether invoked
from the command-line as vacuumdb or invoked from psql (connecting to
localhost) as "vacuum analyze;" the memory error occurs. The logfile
reveals:
ERROR: out of memory
DETAIL: Failed on request of size 536870910.

> You might put a 'ulimit -a' command in your cron script to make sure
> your memory limit settings are propagating correctly...

I created a cron that consisted of just that command (ulimit -a) and the
output revealed nothing abnormal (i.e. max dataseg still 1G, etc). This
occurs outside of cron also, (it was just the failing cronjob that
brought it to my attention). Again, if I log in as myself and try to run
the command vaccumdb -a -z it fails; if I su to root and repeat it works
fine. I am trying to narrow this down to a PostgreSQL issue vs FreeBSD
issue.

Sven