ORA-12505, TNS:listener does not currently know of SID given in connect descriptor error occurs when the listener cannot find any matched SID with the provided SID, preventing it from connecting to the database.The database connection Sid you used is either unavailable or wrongly configured. Oracle Listener discovers a discrepancy between your Sid and the connection descriptor settings. The error ORA-12505, TNS:listener does not currently know of SID given in connect descriptor is thrown when oracle fails to create a connection due to invalid SID provided in the configuration.

Please wait a moment while the Oracle service starts up before attempting to connect again. Run the command lsnrctl services to see what services the listener already has. Verify that the service specified by the SID parameter in the connect descriptor of the net SID used is one that the listener is familiar with. If you used a connect identifier, ensure sure the SID is one that the listener recognises. To resolve the error ORA-12505, TNS:listener does not currently know of SID given in connect descriptor, look for any events in the listener.log file.

The Problem

You’ll be provided the host name, port, user name, password, and service name or Sid when you try to connect to a database. Oracle will wait for connections on the same host name and port when it starts up. The SID is the name of the presently running Oracle instance. The alias for the instance that lets you to connect to it is the service name. You will be unable to connect to the running Oracle database instance if the SID setting is incorrect.The error message ORA-12505, TNS:listener does not currently know of SID given in connect descriptor will be displayed.

Host name : localhost
port      : 1521
sid.      : orclcdb
username  : hr
password  : hr


Status : Failure -Test failed: Listener refused the connection with the following error:
ORA-12505, TNS:listener does not currently know of SID given in connect descriptor

Solution 1

It’s possible that the Oracle server is starting up. Retry the connection after a brief pause. It’s possible that a network outage will occur. This will prevent the connection to the Oracle database from being established. Make that the database is up and operating, and that there are no network issues with it. If you’re having trouble connecting to an Oracle database using the host name, consider using the IP address instead. Ensure that the port configuration and the operating port are same. If you’re connecting using an application, make sure the connection url follows the format.


Solution 2

Check to see if the listen is working properly. You can pause and resume listening if there is a problem. The connection to the specified host and port will be refreshed as a result of this action. Multiple connections may cause the listener to hang. After restarting the listener, try connecting it again. The issue ORA-12514, TNS:listener does not presently know of service requested in connect descriptor, will be resolved as a result of this.

lsnrctl status

lsnrctl stop
lsnrctl start

Solution 3

Check to see if the specified SID corresponds to a valid SID in the Oracle database. The SQL statement below will query the Oracle database for the specified SID. Use the database’s SID if the SID specified in listener.ora varies from the database configuration. This will resolve the issue. ORA-12505: TNS:listener is unaware of the SID specified in the connect descriptor.

select value from v$parameter where name='service_names'


Solution 4

Check the listener.ora file for errors. This is how the configuration should appear. The SID LIST LISTENER will hold the Oracle instance settings. This setup will map GLOBAL DBNAME, SID NAME, and ORACLE HOME in the database. The service names from the preceding query should be the same as the SID NAME. The LISTENER setup determines the PROTOCAL, HOST, and PORT. This is how the LISTENER configuration waits for the database connection to establish.




    (SID_DESC =
      (GLOBAL_DBNAME = orclcdb)
      (SID_NAME = orclcdb)
      (ORACLE_HOME = /u01/app/oracle/product/version/db_1)

      (ADDRESS = (PROTOCOL = TCP)(HOST = = 1521))

#HOSTNAME by pluggable not working rstriction or configuration error.

Solution 5

The SID settings, as well as the listener host and port, are all stored in the tnsnames.ora file. Below is an example tnsnames.ora file that demonstrates SID configuration. Check the SID in tnsnames.ora. Make the modifications specified below if the SID is not configured or is incorrectly configured.




    (ADDRESS = (PROTOCOL = TCP)(HOST = = 1521))
      (SID = orclcdb)

Solution 6

Check the oracle database’s system environment configuration. The proper database that is operating will be displayed in the Oracle database settings. It’s possible that numerous Oracle database versions are installed on the server, causing conflicts. Then /.bash profile, /.bashrc, or /etc/..bashrc will be used to set the environment.

export ORACLE_UNQNAME=orclcdb
export ORACLE_BASE=/u01/app/oracle
export ORACLE_HOME=$ORACLE_BASE/product/version/db_1
export ORACLE_SID=orclcdb
export PATH=/home/oracle/bin:/home/oracle/LDLIB:$ORACLE_HOME/bin:/usr/sbin:$PATH

Solution 7

Finally, while attempting to connect to the database, double-check the settings you gave. If you misspelt the configuration, an error message will appear. Check the configurations below to see whether they match your Oracle database configurations.

Host name : localhost
port      : 1521
sid       : orclcdb
username  : hr
password  : hr

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