Re: ALTER SYSTEM SET command to change postgresql.conf parameters

Discussion around this topic has reached hundreds of messages, and
whilst I have failed to find mention of my following question, I
appreciate it may have already been discussed.

I have noticed that configuration parameters for extensions are only
supported if the server was started with one of the parameters already
being set in postgresql.conf:

# without any mention in postgresql.conf
postgres=# ALTER SYSTEM SET auto_explain.log_verbose = true;
ERROR:  unrecognized configuration parameter "auto_explain.log_verbose"

# with auto_explain.log_verbose = false added to postgresql.conf
postgres=# ALTER SYSTEM SET auto_explain.log_verbose = true;
ALTER SYSTEM

Removing the entry from postgresql.conf, restarting Postgres, setting
it to the default, then restarting again renders it unsettable again:

# removed entry from postgresql.conf and restarted

postgres=# ALTER SYSTEM SET auto_explain.log_verbose = default;
ALTER SYSTEM

# restart postgres

postgres=# ALTER SYSTEM SET auto_explain.log_verbose = true;
ERROR:  unrecognized configuration parameter "auto_explain.log_verbose"

Is this by design?

-- 
Thom