Simon Riggs <simon@2ndquadrant.com> writes:
> I'd also like to see vacuum_delay_point() do a test against
> CountActiveBackends() to see if anything else is running. If there all
> non-autovac processes are idle or waiting, then we should skip the delay
> point, this time only. That way a VACUUM can go at full speed on an idle
> system and slow down when people get active again. It will also help
> when people issue a DDL statement against a table that is currently
> being vacuumed. I've got a patch worked out to do this.
This is exceedingly Postgres-centric thinking. The lack of any other
backends does not mean that the system owner wants Postgres to take over
the machine.
regards, tom lane