Re: Just-in-time Background Writer Patch+Test Results

On Sat, 8 Sep 2007, Tom Lane wrote:

> It might be interesting to consider making the delay auto-tune: if you
> wake up and find nothing (much) to do, sleep longer the next time,
> conversely shorten the delay when work picks up.  Something for 8.4,
> though, at this point.

I have a couple of pages of notes on how to tune the delay automatically. 
The tricky part are applications that go from 0 to full speed with little 
warning; the first few seconds of the stock market open come to mind. 
What I was working toward was considering what you set the delay to as a 
steady-state value, and then the delay cranks downward as activity levels 
go up.  As activity dies off, it slowly returns to the default again.

But I realized that I needed to get all this other stuff working, all the 
statistics counters exposed usefully, and then collect a lot more data 
before I could implement that plan.  Definately something that might fit 
into 8.4, completely impossible for 8.3.

--
* Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD