Lesson 1

The previous module introduced you to many of the issues surrounding the use of the Shared Server and especially some of the ways in which it differs from a dedicated listener.
This module takes a much more practical look at Shared Server , investigating how Shared Server handles various types of incoming requests and how to manage and configure Shared Server for optimal performance.

After completing this module, you should be able to:

1. Identify dispatcher parameters
2. Configure the dispatcher for Shared Server
3. Configure multiple listeners with Shared Server
4. Specify relevant parameters for Shared Server servers
5. Set up connection pooling using Shared Server
6. Monitor Shared Server connections using UNIX and Oracle

The module begins with an examination of dispatcher parameters.

Oracle7 introduced the Multi-Threaded Server (MTS, renamed the shared server in Oracle9i) to allow Oracle to support larger user populations. While shared server and MTS reduced the number of server processes, each client still used its own physical network connection. The resources for network connections aren’t unlimited, so Oracle8 introduced two solutions for increasing the capabilities of the actual network socket layer at the operating-system level:

Allows the client population to share a pool of shared physical network connections. Idle clients transparently "time out", and their network connections are returned to the pool to be used by active clients. Each idle client maintains a virtual connection with Oracle and will get another physical connection when activity resumes. With the Oracle security model, authentication is separate from a specific connection, so a single pooled connection can represent different users at different times. Connection pooling is suitable for applications with clients that connect but are not highly active.

Multi-Threaded Server was replaced by "Oracle Shared Server" beginning with Oracle 9i.Additional background processes may exist when you use certain other features of the database: for example, shared servers (formerly the Multi-Threaded Server or MTS prior to Oracle9i), or job queues and replication.

A client is any application that connects to the Oracle database to send or retrieve data. An Oracle client application can reside on any machine provided it has Oracle client software installed. Oracle Net is a software component that resides on the client and on the Oracle database server. It establishes and maintains the connection between the client application and the server, and exchanges messages between them using industry standard protocols. For the client application and a database to communicate, the client application must specify location details for the database it wants to connect to, and the database must provide some sort of identification or address.