Query Processing

This section describes how the CData Virtuality Server functions: how queries are executed and terminated, and so on.

Here are the main terms we will be using:

• VM or Process – the JBossAS instance running CData Virtuality Server;
• Host – the machine “hosting” one or more VMs;
• Service – the subsystem running in a VM (often in many VMs) and providing a related set of functionality. In addition to these main components, the service platform provides a core set of services available to applications built on top of the service platform. These services are as follows:
  • Session – the service managing active session information;
  • Buffer Manager – the service providing access to data management for intermediate results;
  • Transaction – the service managing global, local, and request scoped transactions. See also the documentation on Transaction Support.