Re: rapid degradation after postmaster restart

On Tue, 2004-03-16 at 23:49, Joe Conway wrote:
> 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.

If memory serves, the problem is that you actually sleep 10ms even when
you set it to 1.  One of the thing changed in Jan's later patch was the
ability to specify how many pages to work on before sleeping, rather
than how long to sleep inbetween every 1 page.  You might be able to do
a quick hack and have it do 10 pages or so before sleeping.

Matthew