ORA-12523: TNS listener could not find instance appropriate for the client connection

Hi,

Sometimes You can get “ORA-12523: TNS:listener could not find instance appropriate for the client connection ” error.

 

Details of error are as follows.

ORA-12523: TNS:listener could not find instance appropriate for the client connection
Cause: The listener could not find any available (database) instances, that are appropriate for the client connection.
Action: Run “lsnrctl services” to ensure that the instance(s) are registered with the listener, and have status READY.

 

 

Check your listener.ora if it contains An extra bracket or missing bracket. If there is missing or extra bracket in the listener.ora, fix it and start listener again.

 

Or This error is related with the listener and registered services of database. Check listener status

$ lsnrctl status listener

Listener should be always started.

 

Check listener services which services are listening.

lsnrctl services <listener name>

 

Check the SID parameter known by the listener. If the right SID specified or not in the listener status.

 

If the related service name and instance don’t exist in the listener status, then set it in the database and register it to database as follows.

 

SQL> alter system set local_listener='(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.63.34)(PORT=1521)))' scope=both;

SQL> alter system register;

 

 

 

Do you want to learn more details about RMAN, then read the following articles.

https://ittutorial.org/rman-backup-restore-and-recovery-tutorials-for-beginners-in-the-oracle-database/

 

About Mehmet Salih Deveci

I am Founder of SysDBASoft IT and IT Tutorial and Certified Expert about Oracle & SQL Server database, Goldengate, Exadata Machine, Oracle Database Appliance administrator with 10+years experience.I have OCA, OCP, OCE RAC Expert Certificates I have worked 100+ Banking, Insurance, Finance, Telco and etc. clients as a Consultant, Insource or Outsource.I have done 200+ Operations in this clients such as Exadata Installation & PoC & Migration & Upgrade, Oracle & SQL Server Database Upgrade, Oracle RAC Installation, SQL Server AlwaysOn Installation, Database Migration, Disaster Recovery, Backup Restore, Performance Tuning, Periodic Healthchecks.I have done 2000+ Table replication with Goldengate or SQL Server Replication tool for DWH Databases in many clients.If you need Oracle DBA, SQL Server DBA, APPS DBA,  Exadata, Goldengate, EBS Consultancy and Training you can send my email adress [email protected].-                                                                                                                                                                                                                                                 -Oracle DBA, SQL Server DBA, APPS DBA,  Exadata, Goldengate, EBS ve linux Danışmanlık ve Eğitim için  [email protected] a mail atabilirsiniz.

Leave a Reply

Your email address will not be published. Required fields are marked *