Re: Perfomance degradation 9.3 (vs 9.2) for FreeBSD

On 2014-04-21 10:45:24 -0400, Tom Lane wrote:
> Andres Freund <andres@2ndquadrant.com> writes:
> > If there are indeed such large regressions on FreeBSD we need to treat
> > them as postgres regressions. It's nicer not to add config options for
> > things that don't need it, but apparently that's not the case here.
>
> > Imo this means we need to add GUC to control wether anon mmap() or sysv
> > shmem is to be used. In 9.3.
>
> I will resist this mightily.  One of the main reasons to switch to mmap
> was so we would no longer have to explain about SysV shm configuration.

It's still explained in the docs and one of the dynshm implementations
is based on sysv shmem. So I don't see this as a convincing reason.

Regressing installed OSs by 15-20% just to save a couple of lines of
docs and code seems rather unconvincing to me.