Feedback-ID: ie3de48e3:Fastmail
Date: Wed, 1 Oct 2025 12:37:20 +0200
From: =?utf-8?Q?=C3=81lvaro?= Herrera <alvherre@kurilemu.de>
To: Peter Smith <smithpb2250@gmail.com>
Cc: "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: pg_createsubscriber --dry-run logging concerns
Message-ID: <202510011031.6emshjc2co4s@alvherre.pgsql>
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On 2025-Oct-01, Peter Smith wrote:

> (code below may not work; it's just for illustrative purposes)
> 
> #define pg_log_info_checkdry(...) do {\
>   if (dry_run)\
>     pg_log_generic(PG_LOG_INFO, PG_LOG_PRIMARY, "[dry-run NOP]" __VA_ARGS__);\
>   else;\
>     pg_log_generic(PG_LOG_INFO, PG_LOG_PRIMARY, __VA_ARGS__);\
>   } while (0);

I like this kind of idea best.  However I think it might be better to do
it the other way around: have the normal pg_log_info() check dry_run,
and have a special one for the messages that are to be identical in
either mode.  I'm not sure how difficult this is to implement, though.

pg_subscriber is not the only program with a dry-run mode; it looks like
pg_archiveclean, pg_combinebackup, pg_resetwal, pg_rewind have one.  Is
it worth maybe doing something at the common/logging.c level rather than
specifically pg_createsubscriber?

-- 
Álvaro Herrera        Breisgau, Deutschland  —  https://www.EnterpriseDB.com/
[…] indem ich in meinem Leben oft an euch gedacht, euch glücklich zu machen. Seyd es!
A menudo he pensado en vosotros, en haceros felices. ¡Sedlo, pues!
		Heiligenstädter Testament, L. v. Beethoven, 1802
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