Dedicated and Shared Connections in Oracle using VB.NET

In this article, we will learn dedicated and shared connections in Oracle.
  • 1929

The dedicate and share connections is the important part of the oracle net services architecture. The dedicate server process means which services only one user process and the shared server process means which can service multiple user process.

Any point of the dedicated and shared connections:

  1. Server Processes
    • Dedicated
    • Shared
      • Override from Client
    • Dispatchers
  2. The Listener

1. Shared Server Processes

The shared server processes are used in the shared server architecture. The server processes is the part of the oracle net server architecture. The client processes ultimately connect to a dispatcher. The PMON process registers the location and load of the dispatchers with the listener, enabling the listener to forward requests to the least loaded dispatcher. Ashared server process, which can service multiple user processes.

The point of the shared server process:

  • Dedicated

  • Dispatchers

  • Shared

    • Override from client

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     listener2.gif
 

Dedicated

The dedicated used in the shared server architecture. The dedicate is the important part of the shared server. Adedicated server process, which services only one user process. Each client process connects to a dedicated server process. The server process is not shared by any other client. The PMON process registers information about dedicated server processes with the listener. This enables the listener to start up a dedicated server process when a client request arrives and forward the request to it.

Dispatchers

A dispatcher can support multiple client connections concurrently. Each client connection is bound to a virtual circuit. A virtual circuit is a piece of shared memory used by the dispatcher for client database connection requests and replies. The dispatcher places a virtual circuit on a common queue when a request arrives. An idle shared server picks up the virtual circuit from the common queue, services the request, and relinquishes the virtual circuit before attempting to retrieve another virtual circuit from the common queue.This approach enables a small pool of server processes to serve a large number of clients.

Shared Process

The shared server process means multiple client server process. The server processes is the part of the oracle net server architecture. Ashared server process, which can service multiple user processes. The shared server process use an override from client.

2. The Listener

The listener used in the shared server architecture in oracle. The database server receives an initial connection from a client application through the listener. The listener is an application positioned on top of the Oracle Net foundation layer. Various layers on the client and database server during an initial connection. The listener brokers client requests, handing off the requests to the Oracle database server. Every time a client requests a network session with a database server, a listener receives the initial request.

Once a client request has reached the listener, the listener selects an appropriate service handler to service the client's request and forwards the client's request to it. The listener determines if a database service and its service handlers are available through service registration.

Some point of the listener architecture:

  1. The database registers information about the services, instances, and service handlers with the listener.
  2. The client makes an initial connection with the listener.
  3. The listener parses the client request and forwards it to the service handler for the database service requested.

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     listener1-in-vb.net.gif 

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