Joe Conway <[EMAIL PROTECTED]> writes: > I have tested Tom's original patch now. The good news -- it works great > in terms of reducing the load imposed by vacuum -- almost to the level > of being unnoticeable. The bad news -- in a simulation test which loads > an hour's worth of data, even with delay set to 1 ms, vacuum of the > large table exceeds two hours (vs 12-14 minutes with delay = 0). Since > that hourly load is expected 7 x 24, this obviously isn't going to work.
Turns the dial down a bit too far then ... > The problem with Jan's more complex version of the patch (at least the > one I found - perhaps not the right one) is it includes a bunch of other > experimental stuff that I'd not want to mess with at the moment. Would > changing the input units (for the original patch) from milli-secs to > micro-secs be a bad idea? Unlikely to be helpful; on most kernels the minimum sleep delay is 1 or 10 msec, so asking for a few microsec is the same as asking for some millisec. I think what you need is a knob of the form "sleep N msec after each M pages of I/O". I'm almost certain that Jan posted such a patch somewhere between my original and the version you refer to above. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org