Tom,
People's opinions on pgbench may vary, so take what I say with a grain
of salt. Here are my thoughts:
1) Test with no less than 200 transactions per client. I've heard with
less than this, your results will vary too much with the direction of
the wind blowing. A high enough value will help rule out some "noise"
factor. If I am wrong, please let me know.
2) How is the database going to be used? What percentage will be
read/write if you had to guess? Pgbench is like a TPC-B with will help
guage the potential throughput of your tps. However, it may not stress
the server enough to help you make key performance changes. However,
benchmarks are like statistics...full of lies <g>.
3) Run not just a couple pgbench runs, but *many* (I do between 20-40
runs) so you can rule out noise and guage improvement on median results.
4) Find something that you test OLTP-type transactions. I used OSDB
since it is simple to implement and use. Although OSDL's OLTP testing
will closer to reality.
Steve Poe