Dispatcher Process (Dnnn) & Shared Server Process (Snnn)

Managing Network Requests Efficiently 🔄

In a shared server environment, multiple client sessions are handled efficiently by these processes.
The dispatcher process (Dnnn) directs incoming network session requests to a pool of shared server processes (Snnn).
Multiple dispatcher processes can exist for a single database instance.

Oracle Net Listener accepts a client connection request and returns the dispatcher’s address.
The client communicates with the dispatcher after connection establishment.
Dispatcher places the client’s request into a request queue in the large pool of the system global area (SGA).
The next available shared server process (Snnn) picks up the request and processes it.
When done, the shared server places the response in the response queue in the large pool.
The dispatcher sends the completed response back to the client.

Both dispatcher (Dnnn) and shared server (Snnn) processes can run as threads or operating system processes.
Dispatchers run in shared server environments and are part of the database instance infrastructure.

Efficiently manages multiple client requests without needing a dedicated server process for each.
Reduces memory and CPU overhead.
Improves scalability and resource utilization in multi-user environments.