Feedback-ID: ia2694551:Fastmail
Date: Thu, 6 Nov 2025 17:01:15 +0100
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Euler Taveira <euler@eulerto.com>
Cc: japin <japinli@hotmail.com>, Andres Freund <andres@anarazel.de>,
	pgsql-hackers@lists.postgresql.org
Subject: Re: log_min_messages per backend type
Message-ID: <202511061543.defy6sciy3p7@alvherre.pgsql>
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On 2025-Nov-06, Euler Taveira wrote:

> +        Valid values are a comma-separated list of <literal>backendtype:level</literal>
> +        and a single <literal>level</literal>. The list allows it to use
> +        different levels per backend type. Only the single <literal>level</literal>
> +        is mandatory (order does not matter) and it is assigned to the backend
> +        types that are not specified in the list.
> +        Valid <literal>backendtype</literal> values are <literal>archiver</literal>,
> +        <literal>autovacuum</literal>, <literal>backend</literal>,
> +        <literal>bgworker</literal>, <literal>bgwriter</literal>,
> +        <literal>checkpointer</literal>, <literal>ioworker</literal>,
> +        <literal>syslogger</literal>, <literal>slotsyncworker</literal>,
> +        <literal>startup</literal>, <literal>walreceiver</literal>,
> +        <literal>walsender</literal>, <literal>walsummarizer</literal>, and
> +        <literal>walwriter</literal>.
> +        Valid <literal>level</literal> values are <literal>DEBUG5</literal>,
> +        <literal>DEBUG4</literal>, <literal>DEBUG3</literal>, <literal>DEBUG2</literal>,
> +        <literal>DEBUG1</literal>, <literal>INFO</literal>, <literal>NOTICE</literal>,
> +        <literal>WARNING</literal>, <literal>ERROR</literal>, <literal>LOG</literal>,
> +        <literal>FATAL</literal>, and <literal>PANIC</literal>.  Each level includes
> +        all the levels that follow it.  The later the level, the fewer messages are sent
> +        to the log.  The default is <literal>WARNING</literal> for all backend types.

I would use <literal>type:level</literal> rather than "backendtype".
Also, the glossary says we have "auxiliary processes" and "backends", so
from the user perspective, these types are not all backends, but instead
process types.

I think the list of backend types is pretty hard to read.  What do you
think about using 
<simplelist type="vert" columns="4">
to create a friendlier representation?  

So you would say something like "Valid types are listed in the table
below, each corresponding to either postmaster, an auxiliary process
type or a backend".  (Eh, wait, you seem not to have "postmaster" in
your list, what's up with that?)

(I'm not sure about making the log levels also a <simplelist>, because
for that list the order matters, and if we have more than one column
then the order is going to be ambiguous, and if we have just one column
it's going to be too tall.  But maybe it's not all that bad?)

-- 
Álvaro Herrera               48°01'N 7°57'E  —  https://www.EnterpriseDB.com/