Andres Freund <andres@anarazel.de> writes:
> The more important part I think is that we solve it via a GUC that can
> be used outside of bgworkers.
Are you proposing an "ignore_datallowconn" GUC? That's a remarkably
bad idea. We don't have infrastructure that would allow it to be set
at an appropriate scope. I can't imagine any good use-case for allowing
it to be on globally; you'd want it to be per-session (or per-bgworker).
But I don't think there's any way to change the system default setting
in time for the setting to take effect during connection startup or
bgworker startup.
Magnus' most recent patch in this thread seems like a fine answer for
bgworkers. You've moved the goalposts into the next county, and the
design you're proposing to satisfy that goal is lousy. It will end
up being a large amount of additional work with no benefit except
being able to use an arguably less ugly (but almost certainly no
shorter) datallowconn override method in pg_upgrade.
regards, tom lane