Horton

Re: Estimating HugePages Requirements?

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: "Bossart, Nathan" <bossartn@amazon.com>
Cc: Justin Pryzby <pryzby@telsasoft.com>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, "tgl@sss.pgh.pa.us" <tgl@sss.pgh.pa.us>, "robertmhaas@gmail.com" <robertmhaas@gmail.com>, "masao.fujii@oss.nttdata.com" <masao.fujii@oss.nttdata.com>, "andres@anarazel.de" <andres@anarazel.de>, "magnus@hagander.net" <magnus@hagander.net>, "mark.dilger@enterprisedb.com" <mark.dilger@enterprisedb.com>, "don@seiler.us" <don@seiler.us>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2021-09-22T03:53:26Z
Lists: pgsql-hackers 
On Tue, Sep 21, 2021 at 04:06:38PM +0000, Bossart, Nathan wrote:
> I was looking at this from the standpoint of keeping the startup steps
> consistent between the modes.  Looking again, I can't think of
> a strong reason to add it to bootstrap mode.  I think the case for
> adding it to single-user mode is a bit stronger, as commands like
> "SHOW shared_memory_size;" currently return 0.  I lean in favor of
> adding it for single-user mode, but it's probably fine either way.

I am not sure either as that's a tradeoff between an underestimation
and no information.  The argument of consistency indeed matters.
Let's see if others have any opinion to share on this point.
--
Michael

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.