public inbox for [email protected]  

help / color / mirror / Atom feed

From: Bertrand Drouvot <[email protected]>
To: Tomas Vondra <[email protected]>
Cc: Jakub Wartak <[email protected]>
Cc: Christoph Berg <[email protected]>
Cc: [email protected]
Subject: Re: failed NUMA pages inquiry status: Operation not permitted
Date: Tue, 27 Jan 2026 06:36:11 +0000
Message-ID: <aXhc28njnkK/[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>
	<CAKZiRmwV_O73DdSosD-k62kS2wWPc3C8mRZY8j9ozfOu5OLLjg@mail.gmail.com>
	<[email protected]>
	<CAKZiRmxiGxA6N0YdtTQiDfd9TByLKtdCnqKWNGZMVTKyHgWw4Q@mail.gmail.com>
	<[email protected]>
	<[email protected]>

Hi,

On Tue, Jan 27, 2026 at 12:32:28AM +0100, Tomas Vondra wrote:
> On 1/16/26 22:29, Tomas Vondra wrote:
> > Hi,
> > 
> > Here's WIP fix for the root cause, i.e. handling status -2 in the two
> > views querying NUMA node for memory pages:
> > 
> > * pg_shmem_allocations_numa
> > * pg_buffercache_numa
> > 
> > We can't prevent -2 from happening - the kernel can move arbitrary pages
> > to swap, we have no control over it. So I think we need to handle -2 as
> > "unknown" node, instead of failing. The patch simply returns NULL
> > instead of the node, but in principle we might return some other value
> > (but IMHO we should not return the raw status, the -2 makes no sense in
> > our context, it's some internal kernel errno).
> > 
> > The pg_buffercache_numa was not failing, it just returned the -2 status
> > verbatim. But I modified it to return NULL, for consistency.
> > 
> > AFAIK this will fix the regression tests too - they only check COUNT(*),
> > not the actual values.
> > 
> > I'm not sure if we need to mention this in the docs. It probably should
> > mention the column can be NULL, which means "unknown node".
> > 
> 
> Pushed and backpatched to 18. Hopefully that fixes this.

Should 09c37015d49665c52ae7eabd5852af36851aede4 be added to .git-blame-ignore-revs?

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com

view thread (83+ messages)  latest in thread

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected], [email protected], [email protected], [email protected]
  Subject: Re: failed NUMA pages inquiry status: Operation not permitted
  In-Reply-To: <aXhc28njnkK/[email protected]>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox