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

On Mon, Dec 23, 2013 at 1:42 PM, Thom Brown <thom(at)linux(dot)com> wrote:
> 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?

I would think that you'd need to have auto_explain loaded in the
backend where you're trying to make a change, but you shouldn't need
the setting to be present in postgresql.conf, I would think.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company