Re: rapid degradation after postmaster restart

Tom Lane wrote:
> Joe Conway <mail(at)joeconway(dot)com> writes:
>
>>Any idea where I can get my hands on the latest version. I found the
>>original post from Tom, but I thought there was a later version with
>>both number of pages and time to sleep as knobs.
>
> That was as far as I got. I think Jan posted a more complex version
> that would still be reasonable to apply to 7.4.

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.

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? If so, I guess I'll get to extracting what I
need from Jan's patch.

Thanks,

Joe