Re: Should we increase the default vacuum_cost_limit?

David Rowley <david.rowley@2ndquadrant.com> writes:
> I agree that vacuum_cost_delay might not be granular enough, however.
> If we're going to change the vacuum_cost_delay into microseconds, then
> I'm a little concerned that it'll silently break existing code that
> sets it.  Scripts that do manual off-peak vacuums are pretty common
> out in the wild.

True.  Perhaps we could keep the units as ms but make it a float?
Not sure if the "units" logic can cope though.

> My vote is to 10x the maximum for vacuum_cost_limit and consider
> changing how it all works in PG13.  If nothing happens before this
> time next year then we can consider making vacuum_cost_delay a
> microseconds GUC.

I'm not really happy with the idea of changing the defaults in this area
and then changing them again next year.  That's going to lead to a lot
of confusion, and a mess for people who may have changed (some) of
the settings manually.

            regards, tom lane