Re: [Util] Warn and Remove Invalid GUCs

Srinath Reddy Sadipiralla <srinath2133@gmail.com> writes:
> the extension is loaded and then i entered the bogus extension GUC into
> postgresql.conf and restarted, i did not observe any complain/warning .

Were you looking in the right place?  I experimented with adding

shared_preload_libraries = 'plpgsql'            # (change requires restart)
plpgsql.bogus = 1

to postgresql.conf.  Restarting the server, I see in the
postmaster log:

2025-05-22 11:16:45.724 EDT [1526138] WARNING:  invalid configuration parameter name "plpgsql.bogus", removing it
2025-05-22 11:16:45.724 EDT [1526138] DETAIL:  "plpgsql" is now a reserved prefix.
2025-05-22 11:16:45.728 EDT [1526138] LOG:  starting PostgreSQL 18beta1 on x86_64-pc-linux-gnu, compiled by gcc (GCC)
8.5.020210514 (Red Hat 8.5.0-26), 64-bit 
... etc etc ...

(I also tried the other order of these settings, to see if that made
any difference, but it didn't.)  I also tried

session_preload_libraries = 'plpgsql'
plpgsql.bogus = 1

and then the complaint comes out during any session start:

$ psql
WARNING:  invalid configuration parameter name "plpgsql.bogus", removing it
DETAIL:  "plpgsql" is now a reserved prefix.
psql (18beta1)
Type "help" for help.

That's all operating as intended, and I'm not seeing how the proposed
patch isn't completely redundant with it.

            regards, tom lane