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

From Bruce Momjian
Subject Re: FEATURE REQUEST: Role vCPU limit/priority
Date
Msg-id ZbAEgJA8WAskN9dI@momjian.us
Whole thread Raw
In response to Re: FEATURE REQUEST: Role vCPU limit/priority  (Andres Freund <andres@anarazel.de>)
List pgsql-hackers
On Tue, Jan 23, 2024 at 10:10:27AM -0800, Andres Freund wrote:
> 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.

FYI, here is an article about priority inversion:

    https://www.geeksforgeeks.org/priority-inversion-what-the-heck/

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Only you can decide what is important to you.



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