Handling ‘ora-12505, Tns:listener Does Not Currently Know Of Sid Given In Connect Descriptor’ In Oracle

Handling “ORA-12505, TNS:listener Does Not Currently Know of SID Given in Connect Descriptor” in Oracle

The “ORA-12505, TNS:listener does not currently know of SID given in connect descriptor” error occurs when a client application attempts to connect to an Oracle database but provides an invalid or unknown Service Identifier (SID). The SID is a unique identifier that specifies the specific Oracle database instance that the client wants to connect to.

Causes:

There are several possible causes for this error:

• Invalid SID: The client application may be specifying an incorrect SID in the connection string.
• Unknown SID: The specified SID may not exist on the Oracle database server. This could happen if the database instance has been renamed, dropped, or is not started.
• Incorrect listener configuration: If the Oracle listener is not properly configured to listen for connections on the correct port or host address, the client application may not be able to establish a connection.

Troubleshooting:

To troubleshoot this error, follow these steps:

1. Verify SID: Ensure that the SID specified in the connection string is correct. Check the Oracle database server’s configuration files or use the tnsping command to confirm the correct SID.
2. Check Oracle Database Instance: Verify that the Oracle database instance associated with the specified SID is running and accessible. Use the sqlplus command or another tool to connect to the database using the correct SID and credentials.
3. Configure Listener: Check the Oracle listener configuration to ensure that it is listening on the correct port and IP address. Use the lsnrctl command to check the listener status and make any necessary adjustments.
4. Restart Services: If needed, restart the Oracle database and listener services to ensure that they are functioning properly.

Solutions:

To resolve the “ORA-12505” error, try the following solutions:

• Use Correct SID: Specify the correct SID in the connection string.
• Create SID: If the specified SID does not exist, create it using Oracle Enterprise Manager (OEM) or the create database command.
• Configure Listener: Ensure that the Oracle listener is listening on the correct port and IP address.
• Restart Services: Restart the Oracle database and listener services if necessary.## Handling “ora-12505, Tns:listener Does Not Currently Know Of Sid Given In Connect Descriptor” In Oracle

Executive Summary

This comprehensive guide provides detailed solutions to resolve ORA-12505 Errors in Oracle. It covers key subtopics such as:

• Verifying SID existence
• Checking listener parameters
• Reviewing network connectivity
• Investigating firewall rules
• Troubleshooting incorrect TNS entries

Introduction

ORA-12505 is a common Oracle error that indicates the listener cannot identify the specified SID (System Identifier) in the connection descriptor. This can be caused by various factors, such as invalid SID, misconfigured listener, or network issues.

Subtopic 1: Verifying SID Existence

• Check Database: Ensure the database instance with the specified SID exists in the Oracle server.
• Inspect TNS Entry: Review the TNS entry in the tnsnames.ora file to confirm its syntax and the correct SID.
• Query Database: Use the SELECT INSTANCE_NAME FROM V$INSTANCE query to retrieve a list of available instance names and verify the presence of the required instance.

Subtopic 2: Checking Listener Parameters

• Check Listener Port: Ensure that the listener is configured with the correct port in the listener.ora file.
• Verify Network Protocol: Check if the listener is accepting connections over the specified network protocol (TCP or IPC).
• Review Listener Status: Use the lsnrctl status command to check the status of the listener and ensure it is running.

Subtopic 3: Reviewing Network Connectivity

• Test Network: Use ping or Telnet to verify network connectivity between the client and the Oracle server.
• Check Firewall Rules: Review the firewall settings to ensure the necessary network ports are open to allow connections to the listener.
• Inspect Client Configuration: Ensure the client is configured with the correct TNS entry and network parameters.

Subtopic 4: Investigating Firewall Rules

• Check Incoming Connections: Ensure that the firewall allows incoming connections on the specified port from the client.
• Review Firewall Logs: Examine the firewall logs to identify any blocked connections or dropped packets related to the Oracle database.
• Contact Firewall Administrator: If necessary, contact the firewall administrator to verify the firewall configuration and make any necessary adjustments.

Subtopic 5: Troubleshooting Incorrect TNS Entries

• Review TNS File: Examine the syntax and parameters specified in the TNS entry within the tnsnames.ora file.
• Test TNS: Use the tnsping command to test the TNS entry and verify connectivity.
• Identify Incorrect Parameters: Check for incorrect or missing parameters, such as SID, host, or port, within the TNS entry.

Conclusion

By meticulously addressing these subtopics, you can effectively resolve “ora-12505, tns:listener does not currently know of sid given in connect descriptor” errors in Oracle. Remember to verify SID existence, check listener parameters, review network connectivity, investigate firewall rules, and troubleshoot incorrect TNS entries to ensure optimal database accessibility.

Keyword Phrase Tags

• ORA-12505 Error
• Oracle SID
• TNS Listener
• Network Connectivity
• Firewall Configuration