Date: Tue, 12 Apr 2022 09:17:23 -0700
From: Nathan Bossart <nathandbossart@gmail.com>
To: Julien Rouhaud <rjuju123@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Andres Freund <andres@anarazel.de>,
	Michael Paquier <michael@paquier.xyz>,
	"Bossart, Nathan" <bossartn@amazon.com>,
	Fujii Masao <masao.fujii@oss.nttdata.com>,
	"wangsh.fnst@fujitsu.com" <wangsh.fnst@fujitsu.com>,
	Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>,
	Greg Sabino Mullane <htamfids@gmail.com>,
	Tom Lane <tgl@sss.pgh.pa.us>,
	"pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
Subject: Re: make MaxBackends available in _PG_init
Message-ID: <20220412161723.GA2062175@nathanxps13>
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On Tue, Apr 12, 2022 at 01:08:35PM +0800, Julien Rouhaud wrote:
> It looks sensible to me, although I think I would apply 0003 before 0002.

Great.

> +   if (process_shared_preload_libraries_in_progress &&
> +       !allow_when_loading_preload_libs)
> +       ereport(ERROR,
> +               (errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
> +                errmsg("cannot change parameters while loading "
> +                       "\"shared_preload_libraries\"")));
> +
> 
> I think the error message should mention at least which GUC is being modified.

My intent was to make it clear that no parameters can be updated while
loading s_p_l, but I agree that we should mention the specific GUC
somewhere.  Maybe this could go in a hint?

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com