Re: Proposal: Shared Work Mem Area

Thanks Stephen.

https://commitfest.postgresql.org/42/3867/ is not exacly what I proposed as new feature to developers.

If I'm not wrong, almost all main memory areas have a fixed size:

shared_buffers
effective_cache_size
wal_buffers

Instead, work_mem is per-process dynamically allocated up to defined size limit.

What I suggested is to replace work_mem from per-process allocation to global and fixed size allocation (see pga_aggregate_target on Oracle) and shared to worker processes.

Let's assume the new parameter name is worker_mem_area and this was set to 8GB: with my proposal method each worker process do not use it's own dedicated work_mem but the shared one.

In this way each worker is also able to peek free pages from the worker_mem_area if needed.

Regards,
Marco

________________________________
Da: Stephen Frost
Inviato: Giovedì, 06 Aprile, 2023 14:43
A: Marco Fortina
Cc: pgsql-general(at)postgresql(dot)org
Oggetto: Re: Proposal: Shared Work Mem Area

Greetings,

* Marco Fortina (marco_fortina(at)hotmail(dot)it) wrote:
> I would like to propose to developers a new feature to replace the private management of the work mem with a management through shared memory: allocated at the start of PostgreSQL this area should be shared to all worker processes as for example Oracle Database PGA do.
>
> This would allow an optimal use of this memory area by limiting only its global maximum limit and not a configuration/allocation at the process level.
>
> What do you think about my proposal?

There's ongoing work to provide a way to have a global maximum limit
which doesn't involve entirely reworking how work_mem works today. The
commitfest entry for that work is here:

https://commitfest.postgresql.org/42/3867/

If you're interested in that, getting additional reviews and comments on
the work would be helpful in moving it forward.

Thanks,

Stephen