On Thu, Oct 19, 2023 at 12:00 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
shihao zhong <zhong950419@gmail.com> writes: > 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.
I don't think there's any chance of getting away with that. As noted upthread, a lot of people use placeholder GUCs as a substitute for a proper session-variable feature. If we ever get real session variables, we could start to nudge people away from using placeholders; but right now too many people would complain about the noise of a warning.
> 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?
No, a per-session SET will override a value coming from the config file. That's independent of whether it's a regular or custom GUC.