Re: FEATURE REQUEST: Role vCPU limit/priority - Mailing list pgsql-hackers

From Andres Freund
Subject Re: FEATURE REQUEST: Role vCPU limit/priority
Date
Msg-id 20240123181027.hoezdrxyf5brsrc5@awork3.anarazel.de
Whole thread Raw
In response to Re: FEATURE REQUEST: Role vCPU limit/priority  (Thomas Kellerer <shammat@gmx.net>)
Responses Re: FEATURE REQUEST: Role vCPU limit/priority
List pgsql-hackers
Hi,

On 2024-01-23 13:09:22 +0100, Thomas Kellerer wrote:
> Yoni Sade schrieb am 21.01.2024 um 19:07:
> > It would be useful to have the ability to define for a role default
> > vCPU affinity limits/thread priority settings so that more active
> > sessions could coexist similar to MySQL resource groups
> > <https://dev.mysql.com/doc/refman/8.0/en/resource-groups.html>.
> 
> To a certain extent, you can achieve something like that using Linux cgroups
> 
> https://www.cybertec-postgresql.com/en/linux-cgroups-for-postgresql/

If you do that naively, you just run into priority inversion issues. E.g. a
backend holding a critical lwlock not getting scheduled for a while because it
exceeded it CPU allocation, preventing higher priority processes from
progressing.

I doubt you can implement this in a robust manner outside of postgres.

Regards,

Andres



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