Andrew Sullivan <andrew@libertyrms.info> writes:
>> I disagree. Triggering a vacuum on a db that is nearly saturating the
>> disk bandwidth has a significant impact.
> Vivek is right about this. If your system is already very busy, then
> a vacuum on a largish table is painful.
> I don't actually think having the process done in real time will
> help, though -- it seems to me what would be more useful is an even
> lazier vacuum: something that could be told "clean up as cycles are
> available, but make sure you stay out of the way." Of course, that's
> easy to say glibly, and mighty hard to do, I expect.
I'd love to be able to do that, but I can't think of a good way.
Just nice'ing the VACUUM process is likely to be counterproductive
because of locking issues (priority inversion). Though if anyone cares
to try it on a heavily-loaded system, I'd be interested to hear the
results...
regards, tom lane
