Anjan,
> From what I know, there is a cache-row-set functionality that doesn't
> exist with the newer postgres...
What? PostgreSQL has always used the kernel cache for queries.
> Concurrent users will start from 1 to a high of 5000 or more, and could
> ramp up rapidly. So far, with increased users, we have gone up to
> starting the JVM (resin startup) with 1024megs min and max (recommended
> by Sun) - on the app side.
Well, just keep in mind when tuning that your calculations should be based on
*available* RAM, meaning RAM not used by Apache or the JVM.
With that many concurrent requests, you'll want to be *very* conservative with
sort_mem; I might stick to the default of 1024 if I were you, or even lower
it to 512k.
--
Josh Berkus
Aglio Database Solutions
San Francisco