generating postgres core files on debian

Hello,

I am trying to debug a problem involving DBD::PgSPI that crashes the
backend. It used to work fine util we installed perl-5.8. How can I get
a core file of a crashed backend on a debian-linux (unstable) machine?

My /etc/security/limits.conf is empty. When I login as root "ulimit -c"
shows a limit of 0. If I set the limit to "unlimited" and logout/login
the limit is back to 0.

Is it sufficient to set the proper limit and then restart postgres in
the same shell to obtain core files in case the backend crashes?

Thanks in advance, cheers,

-- 
ldm@apartia.org