MIME-Version: 1.0
References: <E1w7pJ5-002Q6p-10@gemulon.postgresql.org>
In-Reply-To: <E1w7pJ5-002Q6p-10@gemulon.postgresql.org>
From: Robert Haas <robertmhaas@gmail.com>
Date: Thu, 2 Apr 2026 15:56:26 -0400
Message-ID: 
 <CA+TgmoYsu2+YAo9eLGkDp5VP-pfQ-jOoX382vS4THKHeRTNgew@mail.gmail.com>
Subject: Re: pgsql: Reduce log level of some logical decoding messages from
 LOG to D
To: Fujii Masao <fujii@postgresql.org>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Archived-At: 
 <https://www.postgresql.org/message-id/CA%2BTgmoYsu2%2BYAo9eLGkDp5VP-pfQ-jOoX382vS4THKHeRTNgew%40mail.gmail.com>
Precedence: bulk

On Wed, Apr 1, 2026 at 2:44=E2=80=AFAM Fujii Masao <fujii@postgresql.org> w=
rote:
> Reduce log level of some logical decoding messages from LOG to DEBUG1

Hi,

Apologies for not having noticed this thread before the patch was
committed, but I have some reservations about this change. I agree
that if someone is calling pg_logical_slot_get_changes() regularly, it
isn't good to write a LOG message every time. However, I am concerned
that this may make problems with regular logical decoding much harder
to debug. I see that there was some discussion of adding a GUC to
raise the level back up to LOG, but I feel like that wouldn't help
much. If something goes wrong, enabling the messages for the future
won't tell you what went wrong in the past. I am wondering whether a
better approach might be to set the LOG level based on context -- that
is, if it's actually logical decoding, log this at LOG, but if it's
just someone peeking at a slot or similar, reduce the log level to
DEBUG1 or, really, probably more like DEBUG3.

Thoughts?

--=20
Robert Haas
EDB: http://www.enterprisedb.com