Database Error Messages

Release
toggle
  • 23ai
  • 21c
  • 19c
Updated
Apr 29, 2024

ORA-12505

Cannot connect to database. SID SID_value is not registered with the listener at host_port. (CONNECTION_ID=connection_id)
  • SID_value: Name of the Oracle Database instance on the host computer.
  • host_port: The host and port that the Oracle Database listener process is on.
  • connection_id: The connection ID.

Cause

A listener process initially handles all connections to Oracle Database. The connection request received by the listener specified a system identifier (SID) for an instance (usually a database instance) that either was not dynamically registered with the listener or was not statically configured in the listener's listener.ora configuration file. This error may be a temporary condition that occurs after the listener has started but before the database instance registers with the listener.


Action

Do the following:

  • Check for mistakes in the specified connection string.
  • Check that the SID parameter in the connection string or that the tnsnames.ora file connect descriptor specifies an instance known by the listener.
  • Wait a moment and try to connect again. The database instance registration may not yet be complete.
  • Use the CONNECTION_ID value to track this connection attempt in trace files for further diagnosis.

To find which instances are currently known by the listener:

  • Ask the Database Administrator.
  • Review the connection string shown in the cloud service console.
  • If you have access to the machine where the listener is running, run one of the following:
  • lsnrctl services
  • When a listener is named in the listener.ora file, run: lsnrctl services <listener_name>
  • If an Oracle Connection Manager (Oracle CMAN) proxy listener is named in the cman.ora file, run: cmctl show services -c <cman_name>