Horton

Re: Estimating HugePages Requirements?

Fujii Masao <masao.fujii@oss.nttdata.com>

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From: Fujii Masao <masao.fujii@oss.nttdata.com>
To: Michael Paquier <michael@paquier.xyz>, "Bossart, Nathan" <bossartn@amazon.com>
Cc: 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: 2021-09-08T07:10:41Z
Lists: pgsql-hackers 

On 2021/09/08 12:50, Michael Paquier wrote:
> On Tue, Sep 07, 2021 at 05:08:43PM +0000, Bossart, Nathan wrote:
>> On 9/6/21, 9:00 PM, "Michael Paquier" <michael@paquier.xyz> wrote:
>>> +   sprintf(buf, "%lu MB", size_mb);
>>> +   SetConfigOption("shared_memory_size", buf, PGC_INTERNAL, PGC_S_OVERRIDE);
>>> One small-ish comment about 0002: there is no need to add the unit
>>> into the buffer set as GUC_UNIT_MB would take care of that.  The patch
>>> looks fine.
>>
>> I fixed this in v7.
> 
> Switched the variable name to shared_memory_size_mb for easier
> grepping, moved it to a more correct location with the other read-only
> GUCS, and applied 0002.  Well, 0001 here.

Thanks for adding useful feature!

+		{"shared_memory_size", PGC_INTERNAL, RESOURCES_MEM,

When reading the applied code, I found the category of shared_memory_size
is RESOURCES_MEM. Why? This seems right because the parameter is related
to memory resource. But since its context is PGC_INTERNAL, PRESET_OPTIONS
is more proper as the category? BTW, the category of any other
PGC_INTERNAL parameters seems to be PRESET_OPTIONS.

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION

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.