David Kerr <dmk@mr-paradox.net> wrote:
> My assertian/hope is that the saturation point
> on this machine should be higher than most.
Here's another way to think about it -- how long do you expect your
average database request to run? (Our top 20 transaction functions
average about 3ms per execution.) What does that work out to in
transactions per second? That's the TPS you can achieve *on each
connection* if your pooler is efficient. If you've determined a
connection pool size based on hardware resources, divide your
anticipated requests per second by that pool size. If the result is
less than the TPS each connection can handle, you're in good shape.
If it's higher, you may need more hardware to satisfy the load.
Of course, the only way to really know some of these numbers is to
test your actual application on the real hardware under realistic
load; but sometimes you can get a reasonable approximation from
early tests or "gut feel" based on experience with similar
applications. I strongly recommend trying incremental changes to
various configuration parameters once you have real load, and
monitor the impact. The optimal settings are often not what you
expect.
And if the pooling isn't producing the results you expect, you
should look at its configuration, or (if you can) try other pooler
products.
-Kevin