Re: TODO Done. Superuser backend slot reservations

"Nigel J. Andrews" <nandrews@investsystems.co.uk> writes:
> I was taking the line that the last slots in the array are
> reserved. Those are not going to be taken by non su connections.

But that doesn't do the job, does it?  My view of the feature is that
when there are at least MaxBackends - ReservedBackends slots in use (by
either su or non-su connections) then no new non-su jobs should be let
in.  For example, if the system is full (with a mix of su and non-su
jobs) and one non-su job quits, don't we want to hold that slot for a
possible su connection?

Your approach does have the advantage of being very cheap to test
(I think my semantics would require counting the active backends),
but I'm not sure that it really does what we want.

            regards, tom lane