Re: Allow ALTER SYSTEM SET on unrecognized custom GUCs

I do like the idea that we should keep the set and the altar system with
the same behavior. But one thing I am worried about is the typo detected
here because I usually make that type of mistake myself. I believe we
should have an extra log to explicitly tell the user this is a `custom
variable` guc.

Btw, another aspect I want to better understand is if the superuser session
called pg_reload_conf with custom variables, does that mean these custom
variables will override the other active transaction's SET command?

Thanks,
Shihao

On Wed, Oct 18, 2023 at 1:59 AM Andrei Lepikhov <a(dot)lepikhov(at)postgrespro(dot)ru>
wrote:

> On 18/10/2023 12:15, Tom Lane wrote:
> > Andrei Lepikhov <a(dot)lepikhov(at)postgrespro(dot)ru> writes:
> >> "SET foo.bar TO 'smth'" can immediately alter the placeholder's value.
> >> But what is the reason that "ALTER SYSTEM SET foo.bar TO 'smth'" doesn't
> >> do the same?
> >
> > Because it's not supposed to take effect until you issue a reload
> > command (and maybe not even then, depending on which GUC we're
> > talking about). I certainly think it wouldn't make sense for your
> > own session to adopt the value ahead of others.
>
> Thanks for the answer.
> Introducing the assignable_custom_variable_name can be helpful. The code
> looks good. I think it deserves to be committed - after the indentation
> fix, of course.
>
> --
> regards,
> Andrey Lepikhov
> Postgres Professional
>
>
>
>