Date: Tue, 16 Dec 2025 15:48:38 +0100
From: Christoph Berg <myon@debian.org>
To: Tomas Vondra <tomas@vondra.me>
Cc: Jakub Wartak <jakub.wartak@enterprisedb.com>,
	pgsql-hackers@lists.postgresql.org
Subject: Re: failed NUMA pages inquiry status: Operation not permitted
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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@postgres ERROR:  invalid NUMA node id outside of allowed range [0, 0]: -2
> 2025-12-16 11:49:35.982 UTC [621807] myon@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