The SMP environment product is intended for machines with the following features:
A symmetric multiprocessing operating system
Shared memory over a common bus
1–128 processors
No master processor
Very high throughput
Adaptive Server consists of one or more cooperating processes (called engines), all of which run the server program in parallel. See Figure 20-1.
Figure 20-1: SMP environment architecture
When clients connect to Adaptive Server, the client connections are assigned to engines in a round-robin fashion, so all engines share the work of handling network I/O for clients. All engines are peers, and they communicate via shared memory.
The server engines perform all database functions, including updates and logging. Adaptive Server, not the operating system, dynamically schedules client tasks onto available engines.
The operating system schedules the engine processes onto physical processors. Any available CPU is used for any engine; there is no engine affinity. The processing is called symmetric because the lack of affinity between processes and CPUs creates a symmetrically balanced load.
