Horton

Re: Estimating HugePages Requirements?

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: "Bossart, Nathan" <bossartn@amazon.com>
Cc: Michael Paquier <michael@paquier.xyz>, Fujii Masao <masao.fujii@oss.nttdata.com>, Justin Pryzby <pryzby@telsasoft.com>, Andres Freund <andres@anarazel.de>, Magnus Hagander <magnus@hagander.net>, Mark Dilger <mark.dilger@enterprisedb.com>, Don Seiler <don@seiler.us>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2021-09-10T20:01:23Z
Lists: pgsql-hackers 
On Thu, Sep 9, 2021 at 5:53 PM Bossart, Nathan <bossartn@amazon.com> wrote:
> For 0001, the biggest thing on my mind at the moment is the name of
> the GUC.  "huge_pages_required" feels kind of ambiguous.  From the
> name alone, it could mean either "the number of huge pages required"
> or "huge pages are required for the server to run." Also, the number
> of huge pages required is not actually required if you don't want to
> run the server with huge pages.

+1 to all of that.

> I think it might be clearer to
> somehow indicate that the value is essentially the size of the main
> shared memory area in terms of the huge page size, but I'm not sure
> how to do that concisely.  Perhaps it is enough to just make sure the
> description of "huge_pages_required" is detailed enough.

shared_memory_size_in_huge_pages? It's kinda long, but a long name
that you can understand without reading the docs is better than a
short one where you can't.

-- 
Robert Haas
EDB: http://www.enterprisedb.com

Commits

  1. Silence extra logging when using "postgres -C" on runtime-computed GUCs

  2. doc: Improve postgres command for shared_memory_size_in_huge_pages

  3. Introduce GUC shared_memory_size_in_huge_pages

  4. Support "postgres -C" with runtime-computed GUCs

  5. Make shared_memory_size a preset option

  6. Introduce GUC shared_memory_size

  7. Move the shared memory size calculation to its own function

  8. Add new GUC, max_worker_processes, limiting number of bgworkers.