Listener Registration Process (LREG)

Let’s Talk to the Listener 📞

🧠 What Is LREG?
The Listener Registration Process (LREG) is responsible for registering the database instance and its services with the Oracle Listener, allowing client connections to reach the correct database services.

Think of LREG as the “database spokesperson” — it makes sure the Listener knows who’s available and how to reach them.

🛠️ What LREG Registers

Registered ComponentDescription
Instances 🧠Registers the database instance with the listener.
Services 🛎️Advertises database services (e.g., HR, SALES) so clients can connect properly.
Handlers 🧰Registers components that handle client connections, like dispatchers.
Endpoints 📡Communicates networking details — ports, protocols, etc.

⚙️ Where LREG Runs

  • 📘 Database Instances – Primary location for LREG’s registration responsibilities.
  • 💾 Oracle ASM Instances – Registers ASM-specific services.
  • 🧩 Oracle RAC Environments – Coordinates service registration across cluster nodes.

💡 DBA Tip of the Day

Use the LSNRCTL STATUS command to verify what LREG has registered. If services aren’t appearing, check the LOCAL_LISTENER and SERVICE_NAMES parameters to ensure they’re correctly set.

ADVERTISEMENT