Re: max_connections limit

> > > I have a server running FreeBSD 4.7 and postgres 7.2.4 and when I
> > > set "max_connections" to a value greater than 47, I am unable to
> > > connect to the database server.  I need to be able to raise this
> > > number much higher because every site on this server runs postgres
> > > and at peak times this limit is reached and causes problems.  The
> > > server has 2 gigs of memory.  I would appreciate any suggestion.
> >
> > What's the output in /var/log/pgsql ?  -sc
>
> I have a freeBSD with postgres too and I believe I had to tune the
> kernel for this question

That's what I was getting at actually.  When you install PostgreSQL
via the ports, a file is both sent to the user for visual review, as
well being copied to a file:

     /usr/local/pgsql/post-install-notes

Please review this and see if this doesn't solve your problem.
FreeBSDs SHM settings are low by default and need to be increased for
any kind of production use.

### Begin
To allow many simultaneous connections to your PostgreSQL server, you
should raise the SystemV shared memory limits in your kernel. Here are
example values for allowing up to 180 clients (tinkering in
postgresql.conf also needed, of course):
  options         SYSVSHM
  options         SYSVSEM
  options         SYSVMSG
  options         SHMMAXPGS=65536
  options         SEMMNI=40
  options         SEMMNS=240
  options         SEMUME=40
  options         SEMMNU=120
### End

Please let me know if anyone thinks these numbers should be revised or
could be broken down into a formula for calculation and I'll
incorporate them.  -sc

--
Sean Chittenden