Re: Config reload/restart preview

Magnus Hagander  writes:
>> Should we have a way of previewing changes that would be applied if we
>> reloaded/restarted the server?
>
> Yes, we should.

+1

> This would go well with something I started working on some time ago
> (but haven't actually gotten far on at all), which is the ability for
> pg_ctl to be able to give feedback at all. Meaning a "pg_ctl reload"
> should also be able to tell you which parameters were changed, without
> having to go to the log. Obviously that's almost exactly the same
> feature.

It could probably connect to the server and issue the SQL command to
reload, and that one could probably get enhanced to return modified
variable as NOTICE, or be run with the right client_min_message:
   SELECT pg_reload_conf();

The pg_ctl client would then have to know to display the messages sent
back by the server.

Then back to what Thom actually is asking, I guess that implementing a
SRF that parses the configuration and return something very much like
what we get from pg_settings should be possible, and then it's a matter
of doing an anti-join, as already proposed.

Regards,
-- 
Dimitri Fontaine
http://2ndQuadrant.fr     PostgreSQL : Expertise, Formation et Support