The idea that has been discussed in the past is the concept of maintenance windows, that is for any given period of time, you can set different vacuum thresholds. So at night you might make the thresholds very low so that nearly everything gets vacuumed but during the day you might only vacuum when something really needs it. This accomplishes what you are asking for in a more general way that can accommodate a wide variety of usage patterns.
That really seems like something that, if it's powerful, would also be very complicated. If the autovacuum system could just call a user defined function, all the complexity could be dropped back into the admin's lap (which is fine with me :-).
I am of course ASSuming that it would be simple for autovacuum to call a function if it exists, or take a default action if it does not...
-Glen ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
