Re: Experimental patch for inter-page delay in VACUUM

"Stephen" <jleelim@xxxxxx.com> writes:
> also as there are less processes waiting to complete. I find a value of 1ms
> to 5ms is quite good and will keep system responsive. Going from 10ms to 1ms
> didn't seem to reduce the total vacuum time by much and I'm not sure why.

On most Unixen, the effective resolution of sleep requests is whatever
the scheduler time quantum is --- and 10ms is the standard quantum in
most cases.  So any delay less than 10ms is going to be interpreted as
10ms.

I think on recent Linuxen it's possible to adjust the time quantum, but
whether this would be a net win isn't clear; presumably a shorter
quantum would result in more scheduler overhead and more process-swap
penalties.
        regards, tom lane