Re: failed NUMA pages inquiry status: Operation not permitted

Re: To Tomas Vondra
> I've managed to reproduce it once, running this loop on
> 18-as-of-today. It errored out after a few 100 iterations:
>
> while psql -c 'SELECT COUNT(*) >= 0 AS ok FROM pg_shmem_allocations_numa'; do :; done
>
> 2025-12-16 11:49:35.982 UTC [621807] myon(at)postgres ERROR: invalid NUMA node id outside of allowed range [0, 0]: -2
> 2025-12-16 11:49:35.982 UTC [621807] myon(at)postgres STATEMENT: SELECT COUNT(*) >= 0 AS ok FROM pg_shmem_allocations_numa
>
> That was on the apt.pg.o amd64 build machine while a few things were
> just building. Maybe ENOENT "The page is not present" means something
> was just swapped out because the machine was under heavy load.

I played a bit more with it.

* It seems to trigger only once for a running cluster. The next one
needs a restart
* If it doesn't trigger within the first 30s, it probably never will
* It seems easier to trigger on a system that is under load (I started
a few pgmodeler compile runs in parallel (C++))

But none of that answers the "why".

Christoph