Re: Memory footprint diff between 9.5 and 12

On Thu, 2020-05-07 at 13:33 -0700, Tory M Blue wrote:
> I hadn't noticed this until today, but a running 9.5 system with
> buffers at 10GB starts and has been running years without issues.
> (15GB available)
> Postgres 12 will not start with that configuration, complaining about
> memory availability. So Postgres12 won't start until shared buffers
> is 6GB, but even with that, my DB servers , postgres queries started
> complaining about being unable to allocate memory "unable to
> allocate".
>
> So dropping them to 4GB (on a 15GB system), may help, but did I miss a
> huge note about significant memory changes between 9.5 to 12?
>
> Is there something else I'm missing that on busy systems is important,
> something introduced in 10 or 11 as again I'm not seeing anything
> noted in 12.
> Thanks

Is this running on an otherwise identical system? Or do you have a
different kernel, overcommit settings, or swap configuration?