Shared servers and dedicated servers in Oracle

Oracle creates a server process to process requests from user processes connected to the instance. A server process can be a dedicated server process. At this time, the server process serves only one user process. If the database server is configured as a shared server, the server process can be a shared server process, in this case, the server process can serve multiple user processes.

Generally, it is best to scheduleProgramConnect to and use the shared server process. Because the Shared Server Process maintains the minority processes required to run the instance, the Shared Server process is more efficient. However, in the following scenarios, users and administrators need to directly connect to the instance using a dedicated server process:
Submit a batch processing job
Use revovery manager to back up, restore, or restore a database

When an Oracle database is configured as a shared server, if a dedicated server is required for connection, you must use the network service name configured as the dedicated server for connection. The Shared Server system eliminates the need for dedicated server processes for each connection. In the configuration of the Shared Server, the customer's user process is connected to the scheduler. The scheduler supports multiple concurrent client connections. Each customer connection is connected to a virtual road back. A virtual loop is a shared memory, which is used by the Scheduler for requests and replies to client database connections. When a request arrives, the scheduler places the virtual loop in a public queue. The idle Shared Server will pick up the virtual loop from the public queue, run the request, and discard the virtual loop before obtaining another virtual loop in the public queue. Compared with the dedicated server model, a major advantage of the Shared Server architecture is to support the increasing number of users with fewer system resources.

For more information about how to configure an Oracle database as a shared or dedicated server and modify relevant parameters, see network.