Re: Adding basic NUMA awareness - Preliminary feedback and outline for an extensible approach

Hi,

On Wed, Jul 09, 2025 at 06:40:00AM +0000, Cédric Villemain wrote:
> > On 7/8/25 18:06, Cédric Villemain wrote:
> > I'm not against making this extensible, in some way. But I still
> > struggle to imagine a reasonable alternative policy, where the external
> > module gets the same information and ends up with a different decision.
> >
> > So what would the alternate policy look like? What use case would the
> > module be supporting?
>
>
> That's the whole point: there are very distinct usages of PostgreSQL in the
> field. And maybe not all of them will require the policy defined by
> PostgreSQL core.
>
> May I ask the reverse: what prevent external modules from taking those
> decisions ? There are already a lot of area where external code can take
> over PostgreSQL processing, like Neon is doing.
>
> There are some very early processing for memory setup that I can see as a
> current blocker, and here I'd refer a more compliant NUMA api as proposed by
> Jakub so it's possible to arrange based on workload, hardware configuration
> or other matters. Reworking to get distinct segment and all as you do is
> great, and combo of both approach probably of great interest.

I think that Tomas's approach helps to have more "predictable" performance
expectations, I mean more consistent over time, fewer "surprises".

While your approach (and Jakub's one)) could help to get performance gains
depending on a "known" context (so less generic).

So, probably having both could make sense but I think that they serve different
purposes.

Regards,

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