Re: Problem with PostgreSQL 18 and semaphores

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Sun, Oct 26, 2025 at 08:55:56AM +0100, Martin Husemann wrote:
> On Sat, Oct 25, 2025 at 08:28:13PM +0200, Marc Baudoin wrote:
> > Are the default values for kern.ipc.semmni and kern.ipc.semmns
> > underestimated on NetBSD?
> 
> We have not seen many applications using lots of semaphores so far.
> 
> > Should they be changed in future releases?
> 
> Maybe.
> 
> > Is it a bug in PostgreSQL 18?
> 
> I don't know but we should find out. Maybe ask upstream?
> It is possible that they added code using a lot more semaphores on 
> purpose, and they should document that ... somewhere.
> 
> I am still using postgres 14 and it is happy with the 10/60 defaults.
> 
> (I should prepare for an update once this thread has found a good solution)

I'm using postgresql for netdisco and an internal application.
I have
kern.posix.semmax=256
kern.ipc.semmns=256
kern.ipc.semmni=64

in /etc/sysctl.conf since this system was installed (maybe 10 years
ago) because of postgress. I have postgresql14-server at this time.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--