Re: log_min_messages per backend type

Fujii Masao <masao.fujii@oss.nttdata.com>

From: Fujii Masao <masao.fujii@oss.nttdata.com>

To: Euler Taveira <euler@eulerto.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>

Cc: pgsql-hackers@lists.postgresql.org

Date: 2025-03-06T02:53:54Z

Lists: pgsql-hackers

Commits

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Allow log_min_messages to be set per process type
- 38e0190ced71 19 (unreleased) landed
Assign "backend" type earlier during process start-up
- 0c8e082fba8d 19 (unreleased) landed
Use integer backend type when exec'ing a postmaster child
- f1cd34f95272 19 (unreleased) landed
Sort guc_parameters.dat alphabetically by name
- fce7c73fba4e 19 (unreleased) cited
Create a separate file listing backend types
- dbf8cfb4f02e 19 (unreleased) cited

On 2025/03/05 9:33, Euler Taveira wrote:
>> > +        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>LOGGER</literal>,
>> > +        <literal>SLOTSYNCWORKER</literal>, <literal>WALRECEIVER</literal>,
>> > +        <literal>WALSENDER</literal>, <literal>WALSUMMARIZER</literal>, and
>> > +        <literal>WALWRITER</literal>.

What about postmaster?

For parallel workers launched for parallel queries, should they follow
the backend's log level or the background worker's? Since they operate
as part of a parallel query executed by a backend, it seems more logical
for them to follow the backend's setting.

+	[B_CHECKPOINTER] = "checkpointer",
+	[B_STARTUP] = "backend",	/* XXX same as backend? */

I like the idea of allowing log levels to be set per process.
There were times I wanted to use debug5 specifically for
the startup process when troubleshooting WAL replay. It would be
helpful to distinguish the startup process from a regular backend,
so we can set its log level independently.

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION