Re: Protect syscache from bloating with negative cache entries

Bruce Momjian <bruce@momjian.us> writes:
> On Thu, Jan 24, 2019 at 06:39:24PM +0900, Kyotaro HORIGUCHI wrote:
>> I also thought that there's some other features that is useful if
>> it could be turned on remotely so the remote GUC feature but it
>> was too complex...

> Well, I am thinking if we want to do something like this, we should do
> it for all GUCs, not just for this one, so I suggest we not do this now
> either.

I will argue hard that we should not do it at all, ever.

There is already a mechanism for broadcasting global GUC changes:
apply them to postgresql.conf (or use ALTER SYSTEM) and SIGHUP.
I do not think we need something that can remotely change a GUC's
value in just one session.  The potential for bugs, misuse, and
just plain confusion is enormous, and the advantage seems minimal.

            regards, tom lane