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From: Peter Smith <smithpb2250@gmail.com>
Date: Thu, 11 Dec 2025 18:29:07 +1100
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Subject: Re: [Proposal] Adding Log File Capability to pg_createsubscriber
To: Gyan Sreejith <gyan.sreejith@gmail.com>
Cc: pgsql-hackers@lists.postgresql.org, vignesh C <vignesh21@gmail.com>
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On Wed, Dec 10, 2025 at 9:17=E2=80=AFAM Gyan Sreejith <gyan.sreejith@gmail.=
com> wrote:
>
> Background:
>
> pg_createsubscriber currently outputs all messages (internal validation m=
essages, standby server start/stop logs, recovery progress output, and outp=
ut from utilities) directly to the console. As a result, users may find deb=
ugging and handling errors difficult. It would be more convenient if messag=
es were separated and stored in different log files. There is already a sim=
ilar implementation in pg_upgrade.
>
> Proposed Solution:
>
> Based on issues mentioned previously, I would like to propose a new argum=
ent -l <logdir> which can be specified for pg_createsubscriber. Using it wo=
uld create the following log files:
>
> logdir/pg_createsubscriber_server.log which captures all logs related to =
starting and stopping the standby server.
>
> logdir/pg_createsubscriber_resetwal.log which captures the output of pg_r=
esetwal
>
> logdir/pg_createsubscriber_internal.log which captures internal diagnosti=
c output from pg_createsubscriber (validations, checks, etc.)
>
> Overall, this proposed solution could make the pg_createsubscriber comman=
d output messages more organized. The command would be easier to use as use=
rs will only have to read individual log files rather than parse through lo=
ts of possibly irrelevant output messages. I have attached the patch for th=
is change.
>
> Special thanks to Vignesh C. for his offlist guidance on this project.
>
>
> Regards, Gyan Sreejith
>

Hi Gyan.

I haven't yet looked at this patch in any detail, but here are some
quick comments:

=3D=3D=3D=3D=3D=3D

1.
+ printf(_("  -l, --logdir=3DLOGDIR             location for the new log
directory\n"));

The patch is missing SGML docs updates for pg_createsubscriber new
option, and any explanation of the split of logfiles.

2.
I might be mistaken, but IIUC it seems the splitting of the logfile
only works when --logdir is specified. Is that correct?
Why should --logdir have any side-effect other than assigning the log
destination folder?

=3D=3D=3D=3D=3D=3D
Kind Regards,
Peter Smith.
Fujitsu Australia