By Brian Fitzgerald

Introduction

By trial and error, I identify what Oracle Database instance states correspond to listener status READY, UNKNOWN, and BLOCKED.

Details

I have recorded the listener status for various database states. In some cases, the listener was reloaded or restarted.

Database open READ WRITE:

Service "EQTRD" has 2 instance(s).
  Instance "EQTRD", status UNKNOWN, has 1 handler(s) for this service...
  Instance "EQTRD", status READY, has 1 handler(s) for this service...

Shutdown the database

Service "EQTRD" has 1 instance(s).
  Instance "EQTRD", status UNKNOWN, has 1 handler(s) for this service...

Delete the static listener and reload the listener.

[none]

Startup nomount

Service "EQTRD" has 1 instance(s).
  Instance "EQTRD", status BLOCKED, has 1 handler(s) for this service...

Reload

Service "EQTRD" has 1 instance(s).
  Instance "EQTRD", status BLOCKED, has 1 handler(s) for this service...

Stop and start the listener.

Service "EQTRD" has 1 instance(s).
  Instance "EQTRD", status BLOCKED, has 1 handler(s) for this service...

Note that reloading or restarting the listener does not clear a BLOCKED state.

Mount

Service "EQTRD" has 1 instance(s).
  Instance "EQTRD", status READY, has 1 handler(s) for this service...

Startup force nomount

Service "EQTRD" has 1 instance(s).
  Instance "EQTRD", status BLOCKED, has 1 handler(s) for this service...

Re-enable the static listener

Service "EQTRD" has 2 instance(s).
  Instance "EQTRD", status UNKNOWN, has 1 handler(s) for this service...
  Instance "EQTRD", status BLOCKED, has 1 handler(s) for this service...

Mount

Service "EQTRD" has 2 instance(s).
  Instance "EQTRD", status UNKNOWN, has 1 handler(s) for this service...
  Instance "EQTRD", status READY, has 1 handler(s) for this service...

Restricted session

Service "XIENT" has 1 instance(s).
  Instance "XIENT", status RESTRICTED, has 1 handler(s) for this service...

Summary

Here is a summary of listener status and interpretation.

status	interpretation
BLOCKED	nomount
UNKNOWN	static listener
READY	mounted or open. Dymamically registered
RESTRICTED	restricted session