The cache service moves the SmartPlant Foundation in process application cache to an out of process application cache. By moving the caching mechanism outside of the SmartPlant Foundation server, the system can better use the multiple worker processes feature available on the application pool of your primary SmartPlant Foundation site. The server communicates with the cache service to get any information about the configuration settings, such as the schema and administration data.
The cache service is a separate Windows Communication Foundation (WCF) service, hosted in Internet Information Services (IIS), that uses httpcontext to persist the cached information, as well as expose a number of highly-optimized contracts. This WCF service is exposed to the SmartPlant Foundation Server, through a class called SPFCache. This class controls all calls to the cache service. The SPFApplicationContext class caches certain information as it is retrieved from the cache and decides whether to use the SPFCache class to talk across the process to the cache service.
The maximum number of worker processes that can be configured for the license, cache,
and configuration services application pools is limited to one. Multiple worker processes
are not supported for these application pools.