SQL Server Analysis Services Querying Architecture

 SQL Server Analysis Services  Querying Architecture

To make the querying experience as fast as possible for end users, the Analysis Services querying architecture provides several components that work together to efficiently retrieve and evaluate data. Figure 1 identifies the three major operations that occur during querying: session management, MDX query execution, and data retrieval as well as the server components that participate in each operation.

Figure 1   Analysis Services querying architecture

Session management

Client applications communicate with Analysis Services using XML for Analysis (XMLA) over TCP IP or HTTP. Analysis Services provides an XMLA listener component that handles all XMLA communications between Analysis Services and its clients. The Analysis Services Session Manager controls how clients connect to an Analysis Services instance. Users authenticated by Microsoft® Windows and who have rights to Analysis Services can connect to Analysis Services. After a user connects to Analysis Services, the Security Manager determines user permissions based on the combination of Analysis Services roles that apply to the user. Depending on the client application architecture and the security privileges of the connection, the client creates a session when the application starts, and then reuses the session for all of the user’s requests. The session provides the context under which client queries are executed by the Query Execution Engine. A session exists until it is either closed by the client application, or until the server needs to expire it. For more information regarding the longevity of sessions,