Re: adduser is missing --system

Michael Paquier <michael(dot)paquier(at)gmail(dot)com> writes:
> Please note as well that this has been added to the documentation of Postgres
> 10 with this commit:

Yeah. I think Peter should back-patch that, but he hasn't yet.

The issue might be moot as of v10 anyway, because of this other commit:

Author: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Branch: master Release: REL_10_STABLE [ecb0d20a9] 2016-10-09 18:03:45 -0400

Use unnamed POSIX semaphores, if available, on Linux and FreeBSD.

We've had support for using unnamed POSIX semaphores instead of System V
semaphores for quite some time, but it was not used by default on any
platform. Since many systems have rather small limits on the number of
SysV semaphores allowed, it seems desirable to switch to POSIX semaphores
where they're available and don't create performance or kernel resource
problems. Experimentation by me shows that unnamed POSIX semaphores
are at least as good as SysV semaphores on Linux, and we previously had
a report from Maksym Sobolyev that FreeBSD is significantly worse with
SysV semaphores than POSIX ones. So adjust those two platforms to use
unnamed POSIX semaphores, if configure can find the necessary library
functions. If this goes well, we may switch other platforms as well,
but it would be advisable to test them individually first.

We didn't think about the systemd angle at the time, but this change
might make PG reasonably systemd-proof even without direct protection
from RemoveIPC. I've not tried to experiment though.

regards, tom lane