Summary: in this tutorial, you will learn about the Oracle listener and how to use the listener control commands to manage the listener.
Introduction to the Oracle Listener
The listener is a separate database server process that runs locally on the database server or remotely on the Oracle RAC environment.
This picture shows the Oracle Database architecture and where the listener locates:
When a client request comes, the listener first receives it. And then it establishes a connection between the client and the database instance.
Once the client is connected to the database instance successfully, it hands over the client connection to the server process.
If the listener stops running, you cannot connect to the Oracle Database anymore. However, all the existing connections will not be affected.
Oracle Listener control commands
To launch the listener control, you use the LSNCTRL command from the command line on Windows or terminal on Linux: