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

On Mon, Dec 23, 2013 at 2:19 PM, Thom Brown <thom@linux.com> wrote:
>> 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.
>
> This appears to be the case.  I hadn't set the library to be loaded in
> the config.
>
> I guess therefore it follows that arbitrary configuration parameters
> aren't supported (e.g. moo.bark = 5), only pre-defined ones.

Yeah, and that's by design.  Otherwise, it would be too easy to set a
config parameter to a value that wasn't legal, and therefore make the
server fail to start.  moo.bark = 5 likely won't cause any problems,
but auto_explain.log_verbose = fasle could.  By insisting that the
module providing the GUC be loaded, we can sanity-check the value at
the time it gets set.

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