> I am planning to use PostGreSQL to upgrade an existing Foxpro system to > client/server. > My question is what sort of hardware will I need to get a good response > time from > the system ? > There are around 80 PC's networked together, running Windows and I plan > to run > PostGreSQL on a top of the range PIII hopefully. How much RAM will I > need? > The system is not huge, the largest tables have around 50,000 records in > them, > the entire system is less than 100mb That depends on how many concurrent clients will run on your system. If you plan 80, you will need fair amount of memory, say 100MB, for the backends themselves. Plus 100MB RAMs will also help you to cache entire DB in the OS's buffer cache, if your system runs on Linux box, that is very aggressive with file caching (Not sure with other OSs). Note that increasing the -B option does not help boosting the performance of your system. I don't know why but I guess PostgreSQL has a potential problem with the shared buffer cache system. Talking about number of CPUs, I observed 2 CPUs was best for Linux 2.2.x kernels on a very busy system (with 128 concurrent users). Interestingly, 4 CPUs showed no better performance than single CPU. Again not sure for other OSs, though. BTW, PostgreSQL 7.0 will come with a small benchmarking tool called "pgbench" which can emulate number of concurrent clients. You might want to see how many concurrent transactions your system can process by using it before starting to build the production system. -- Tatsuo Ishii
