Problem with PostgreSQL 18 and semaphores

[Marc Baudoin <babafou%babafou.eu.org@localhost>]

Hi,

I can't get PostgreSQL 18 (databases/postgresql18-server) to work
on two NetBSD/amd64 10.1 systems (so I suppose the problem is
more widespread).  During the initial start after installing (so
this is the initdb step):

FATAL:  n'a pas pu créer des sémaphores : No space left on device
DÉTAIL:  L'appel système qui a échoué était semget(2291207, 17, 03600).
ASTUCE :  This error does *not* mean that you have run out of disk space.  It occurs when either the system limit for the maximum number of semaphore sets (SEMMNI), or the system wide maximum number of semaphores (SEMMNS), would be exceeded.  You need to raise the respective kernel parameter.  Alternatively, reduce PostgreSQL's consumption of semaphores by reducing its "max_connections" parameter.
The PostgreSQL documentation contains more information about configuring your system for PostgreSQL.

Default values are:

kern.ipc.semmni = 10
kern.ipc.semmns = 60

I tried to find the minimum combination to make PostgreSQL 18
work, it's (on my system, I don't know if the machine matters):

kern.ipc.semmni=11
kern.ipc.semmns=187

Lesser values don't work.

Are the default values for kern.ipc.semmni and kern.ipc.semmns
underestimated on NetBSD? Should they be changed in future
releases? Is it a bug in PostgreSQL 18? Or should a MESSAGE file
be added to databases/postgresql18-server to inform people
wanting to run PostgreSQL on NetBSD they need to increase
kern.ipc.semmni and kern.ipc.semmns?

I didn't have any issues about semaphores with previous versions
of PostgreSQL on NetBSD (for the last 28 years).

Thanks.