Though usually considered part of the server, the server-based information store provider has both a server and a client component. Each component uses its own memory space in which it manipulates message objects. As shown in the following illustration, some of the message’s properties exist on the message object on the client and some exist on the server.
Message properties stored on both client and server
Applications make calls to the client component of the information store provider, and the store provider creates RPCs when it must get information from the information store component located on the server. This mechanism hides from applications the fact that the information store provider has a server component in addition to its client component. However, an understanding of this mechanism can be used when designing an application to optimize its performance.
Some operations on the store are very efficient because they can be serviced locally on the client. Others can become very I nefficient when they require repeated RPCs to the server. Some properties are stored — and can be retrieved — from the client without an RPC.
For more information, see Reducing the Number of RPCs.