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On Tue, 4 Mar 2008, Ivan Voras wrote:

> I'm curious about the math behind this - is ~4000 burst or sustained
> rate?

Average, which is not quite burst or sustained.  No math behind it, just 
looking at a few samples of pgbench data on similar hardware.  A system 
like this one is profiled at 
http://www.kaltenbrunner.cc/blog/index.php?/archives/21-8.3-vs.-8.2-a-simple-benchmark.html 
for example.

> For common BBU cache sizes (256M, 512M), filling that amount with data 
> is pretty trivial.

I don't have any good numbers handy but I think the burst is >6000, you 
only get that for a few seconds before all the caches fill and the rate 
drops considerably.

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