Re: doc: Improve description of io_combine_limit and io_max_combine_limit GUCs

On Thu, Nov 6, 2025 at 9:00 AM Chao Li <li(dot)evan(dot)chao(at)gmail(dot)com> wrote:
>
>
>
> > On Nov 5, 2025, at 21:58, Karina Litskevich <litskevichkarina(at)gmail(dot)com> wrote:
> >
> >
> >
> > I'm attaching these changes as a separate patch just in case. You can
> > squash them if you like. Not sure what to do with the commitfest entry.
> > Should I change it back to Needs review?
> >
> > Best regards,
> > Karina Litskevich
> > Postgres Professional: http://postgrespro.com/
> > <v2-0002-doc-Fix-description-of-GUCs-with-PGC_POSTMASTER-c.patch><v2-0001-doc-Improve-description-of-io_combine_limit-and-i.patch>
>
> ```
> - This parameter can only be set in the <filename>postgresql.conf</filename>
> - file or on the server command line.
> + This parameter can only be set at server start.
> ```
>
> I think this change will lose information. Actually, I think that even the original message is not accurate enough. For PGC_POSTMASTER parameters, there are 3 ways to update their values:
>
> * Editing postgres.conf
> * server command line
> * ALTER SYSTEM, updating postgres.auto.conf
>
> But all require a server restart. The original doc misses “ALTER SYSTEM”, and your change just hides all methods. So I would suggest:
>
> ```
> This parameter can only be set at server start (for example, in postgresql.conf, via ALTER SYSTEM, or on the server command line).
> ```
>
> Fujii-san, what do you think?

The general information about how to set GUC parameters is already explained
at the top of config.sgml, which seems sufficient to me. So I don't think it's
an improvement to update the description this way for each parameter.

Regards,

--
Fujii Masao