Alvaro Herrera <alvherre@2ndquadrant.com> writes:
> Claudio Freire escribi�:
>> If you ask me, I'd like autovac to know when not to run (or rather
>> wait a bit, not forever), perhaps by checking load factors or some
>> other tell-tale of an already-saturated I/O system.
> We had a proposed design to tell autovac when not to run (or rather,
> when to switch settings very high so that in practice it'd never run).
> At some point somebody said "but we can just change autovacuum=off in
> postgresql.conf via crontab when the high load period starts, and turn
> it back on afterwards" --- and that was the end of it.
The hard part of this is that shutting down autovacuum during heavy
load may be exactly the wrong thing to do.
regards, tom lane