Oracle in a Nutshell

Shared Servers

Normally, Oracle Net Services creates a single dedicated server process for each user connection. Each server process requires some memory overhead to maintain, even if the process is not doing any active work.

To avoid the excessive use of these connection resources, Oracle Net Services provides a feature called Shared Server, called Multi-Threaded Server (or MTS) prior to Oracle9i. A Shared Server is a server process that can be used for more than one user connection. Instead of creating a dedicated server process, the Shared Server feature uses the listener to route a connection request through a dispatcher. The dispatcher assumes the responsibility of coordinating communication between the database and the client, and routes subsequent requests to one of a number of Shared Servers.

You can have more than one dispatcher process and can configure the number of Shared Servers for an instance. You can have both dedicated and Shared Servers on the same instance. For example, you could create different service names for the same instance, one for dedicated server processes and one for Shared Servers.

Shared Servers are initialized by specifying the appropriate parameters in the instance initialization file, not in any of the Oracle Net Services configuration files described in this chapter. For more details on these initialization parameters, see Chapter 2 TNSNAMES.ORA file or the SQLNET.ORA file.

Shared Servers work best in an environment in which many users are accessing ...