It is important that you choose the right number of engines for Adaptive Server. Here are some guidelines:
Never have more engines than CPUs. Doing so may slow performance. If a CPU goes offline, use sp_configure to reduce the max online engines configuration parameter by 1 and restart Adaptive Server.
Have only as many engines as you have usable CPUs. If there is a lot of processing by the client or other non-Adaptive Server processes, then one engine per CPU may be excessive. Remember, too, that the operating system may take up part of one of the CPUs.
Have enough engines. It is good practice to start with a few engines and add engines when the existing CPUs are almost fully used. If there are too few engines, the capacity of the existing engines will be exceeded and bottlenecks may result.
