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  1. Adjust documentation for configuring Linux huge pages.

  1. Doc: shared_memory_size_in_huge_pages with the "SHOW" command.

    Yuki Seino <seinoyu@oss.nttdata.com> — 2024-10-11T08:25:04Z

    Hello,

Add a reference method for shared_memory_size_in_huge_pages
with the "SHOW" command.

The current documentation explains the use of the postgres -C command,
but this method may be limited in DBaaS or managed service environments.
In particular, CloudNativePG does not allow the server to be stopped,
making the execution of $ postgres -C impossible.

Alternatively, the "SHOW" command can be used, though the documentation 
states,
"Note that the server must be shut down to view this runtime-computed 
parameter.[1]"
This wording could be misunderstood to imply that the parameter cannot 
be accessed
while the server is running.

[1] - 
https://www.postgresql.org/docs/devel/kernel-resources.html#LINUX-HUGE-PAGES

Regards,
--
Yuki Seino
NTT DATA CORPORATION

  2. Re: Doc: shared_memory_size_in_huge_pages with the "SHOW" command.

    Michael Paquier <michael@paquier.xyz> — 2024-10-16T00:31:49Z

    On Fri, Oct 11, 2024 at 05:25:04PM +0900, Seino Yuki wrote:
> Alternatively, the "SHOW" command can be used, though the documentation
> states,
> "Note that the server must be shut down to view this runtime-computed
> parameter.[1]"
> This wording could be misunderstood to imply that the parameter cannot be
> accessed
> while the server is running.

I am not sure that neither mentioning nor recommending SHOW for this
area is a good idea, the point being to encourage its use before the
server is running as we don't want to allocate anything when tuning
it.

Point taken that the current wording can be confusing because of the
"*must* be shut down".  How about doing a simpler s/must/should/ for a
softer wording?
--
Michael

  3. Re: Doc: shared_memory_size_in_huge_pages with the "SHOW" command.

    Nathan Bossart <nathandbossart@gmail.com> — 2024-10-16T01:26:06Z

    On Wed, Oct 16, 2024 at 09:31:49AM +0900, Michael Paquier wrote:
> I am not sure that neither mentioning nor recommending SHOW for this
> area is a good idea, the point being to encourage its use before the
> server is running as we don't want to allocate anything when tuning
> it.

Agreed.

> Point taken that the current wording can be confusing because of the
> "*must* be shut down".  How about doing a simpler s/must/should/ for a
> softer wording?

Well, the point is that you can't use "postgres -C" to view this GUC while
the server is running.  I can see how the present wording might be
misinterpreted, though.  Perhaps we should change this sentence to
something like:

	Note that the server must be shut down to view this runtime-computed
	parameter with the postgres command.

-- 
nathan

  4. Re: Doc: shared_memory_size_in_huge_pages with the "SHOW" command.

    David G. Johnston <david.g.johnston@gmail.com> — 2024-10-16T01:46:44Z

    On Friday, October 11, 2024, Seino Yuki <seinoyu@oss.nttdata.com> wrote:

>
>
> The current documentation explains the use of the postgres -C command,
> but this method may be limited in DBaaS or managed service environments.
> In particular, CloudNativePG does not allow the server to be stopped,
> making the execution of $ postgres -C impossible.


If your environment doesn’t allow shutting down the Postgres service it
seems highly unlikely you’d be able to perform the other low-level
operating system actions required here as well.

I think the wording is fine as-is, though for consistency with an earlier
mention on the page we could instead write:

This parameter can be viewed before starting the server with a postgres command
like:

David J.

  5. Re: Doc: shared_memory_size_in_huge_pages with the "SHOW" command.

    Michael Paquier <michael@paquier.xyz> — 2024-10-16T05:18:16Z

    On Tue, Oct 15, 2024 at 08:26:06PM -0500, Nathan Bossart wrote:
> Well, the point is that you can't use "postgres -C" to view this GUC while
> the server is running.  I can see how the present wording might be
> misinterpreted, though.  Perhaps we should change this sentence to
> something like:
> 
> 	Note that the server must be shut down to view this runtime-computed
> 	parameter with the postgres command.

I'm OK with the "postgres command" addition.
--
Michael

  6. Re: Doc: shared_memory_size_in_huge_pages with the "SHOW" command.

    Fujii Masao <masao.fujii@oss.nttdata.com> — 2024-10-16T06:31:05Z

    
On 2024/10/16 14:18, Michael Paquier wrote:
> On Tue, Oct 15, 2024 at 08:26:06PM -0500, Nathan Bossart wrote:
>> Well, the point is that you can't use "postgres -C" to view this GUC while
>> the server is running.  I can see how the present wording might be
>> misinterpreted, though.  Perhaps we should change this sentence to
>> something like:
>>
>> 	Note that the server must be shut down to view this runtime-computed
>> 	parameter with the postgres command.
> 
> I'm OK with the "postgres command" addition.

Another idea is to use the same wording as for num_os_semaphores in runtime.sgml, like this:

     This parameter can be viewed
     before starting the server with a <command>postgres</command> command like:

Regards,

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

  7. Re: Doc: shared_memory_size_in_huge_pages with the "SHOW" command.

    Nathan Bossart <nathandbossart@gmail.com> — 2024-10-16T14:44:27Z

    On Wed, Oct 16, 2024 at 03:31:05PM +0900, Fujii Masao wrote:
> Another idea is to use the same wording as for num_os_semaphores in runtime.sgml, like this:
> 
>     This parameter can be viewed
>     before starting the server with a <command>postgres</command> command like:

WFM

-- 
nathan

  8. Re: Doc: shared_memory_size_in_huge_pages with the "SHOW" command.

    Yuki Seino <seinoyu@oss.nttdata.com> — 2024-10-17T05:07:32Z

    Thank you, everyone.

> the point being to encourage its use before the server is running
> as we don't want to allocate anything when tuning it.
I was mistaken and now understand that it needs to be run before the 
server is running.

>> Another idea is to use the same wording as for num_os_semaphores in 
>> runtime.sgml, like this:
> 
> WFM
I've fixed the patch and will register it in the CF.

Regards,
--
Yuki Seino
NTT DATA CORPORATION

  9. Re: Doc: shared_memory_size_in_huge_pages with the "SHOW" command.

    Nathan Bossart <nathandbossart@gmail.com> — 2024-10-17T21:59:54Z

    On Thu, Oct 17, 2024 at 02:07:32PM +0900, Seino Yuki wrote:
> I've fixed the patch and will register it in the CF.

Thanks.  Here is what I have staged for commit.

-- 
nathan

  10. Re: Doc: shared_memory_size_in_huge_pages with the "SHOW" command.

    Michael Paquier <michael@paquier.xyz> — 2024-10-17T22:10:08Z

    On Thu, Oct 17, 2024 at 04:59:54PM -0500, Nathan Bossart wrote:
> Thanks.  Here is what I have staged for commit.

Fine by me.  Thanks.
--
Michael

  11. Re: Doc: shared_memory_size_in_huge_pages with the "SHOW" command.

    Fujii Masao <masao.fujii@oss.nttdata.com> — 2024-10-18T05:47:37Z

    
On 2024/10/18 7:10, Michael Paquier wrote:
> On Thu, Oct 17, 2024 at 04:59:54PM -0500, Nathan Bossart wrote:
>> Thanks.  Here is what I have staged for commit.
> 
> Fine by me.  Thanks.

LGTM, too. Thanks!

Regards,

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

  12. Re: Doc: shared_memory_size_in_huge_pages with the "SHOW" command.

    Nathan Bossart <nathandbossart@gmail.com> — 2024-10-18T15:22:51Z

    On Fri, Oct 18, 2024 at 02:47:37PM +0900, Fujii Masao wrote:
> On 2024/10/18 7:10, Michael Paquier wrote:
>> Fine by me.  Thanks.
> 
> LGTM, too. Thanks!

Committed.

-- 
nathan