If your database server is sharing hardware with another use, particularly the common situation where a database-driven application is installed on the same system, you cannot be nearly as aggressive in your tuning as described in the last section. An exact procedure is harder to outline. What you should try to do is use tuning values for the memory-related values on the low side of recommended practice:
shared_buffersat first, even on platforms where more would normally be advised
effective_cache_sizeto 50 percent or less of system RAM, perhaps less if you know your application is going to be using a lot of it
The other suggestions in the ...