A brief analysis of the reasons and solutions for the 12154 error reported by Oracle

Oracle is one of the most widely used relational database management systems, but sometimes errors are inevitable. This article will introduce one of the more common errors - error 12154, and how to solve it.

1. Cause of error 12154

Error 12154 is usually caused by the Oracle client being unable to find the corresponding service when connecting to the server, or the service name being filled in incorrectly. Specifically, there are several possibilities:

1) The service name is filled in incorrectly. Example: The instance name is orcl, and the client input service name is orcl1, etc.

2) TNS service configuration problem. The TNS service is responsible for forwarding client requests to the corresponding instances. If there is a problem with the configuration of the TNS service, it may also result in the inability to connect to the specified instance.

3) The IP address or port number is incorrectly filled in. When connecting to the server, the Oracle listening port used by the client is 1521 by default. If the target port is occupied or the listening port changes, you cannot connect to the specified Oracle instance.

2. Solution

The process of solving Oracle error 12154 is mainly to find the cause of the error and take corresponding solutions. Here are some solutions and strategies I’ve put together.

1) Confirm whether the TNS service is configured correctly. You should confirm whether the TNS services and Listener status are normal in Oracle Net Configuration Assistant. You can confirm whether the listener is started successfully by executing the lsnrctl status command.

2) Confirm whether the service name is filled in correctly. You should check whether the client's service name is the same as the server's service name, which can be verified through the tnsping command.

3) Confirm whether the network connection is normal. You can confirm whether the network connection is normal through ping test, telnet connection, traceroute, etc.

4) Oracle client version compatibility issue. Sometimes the client version is too low and is incompatible with the server version, which can also cause error 12154.

5) Confirm whether the IP address and port number are correct. For example, check the client connection URL (in the form: 'jdbc:oracle:thin:/@::') to confirm the IP address and port number is it right or not.

6) Add the correct service name and IP address information to the tnsnames.ora file, with the keyword "(DESCRIPTION =(ADDRESS_LIST =(ADDRESS =(PROTOCOL = TCP)(Host = IP address)(Port = Port )))(CONNECT_DATA =(SERVICE_NAME = instance name)))"

The above are some common solutions and strategies. No matter what method we take, we should first confirm the source of the error and then troubleshoot. If you still cannot solve the problem, please try the following other methods:

3. Other solutions

1) Create a new connection. If you cannot determine the source of the error, you can try to create a new connection directly and enter the correct instance name, user name, password and other information. If you can connect successfully, it means that the problem lies in the previous connection parameter configuration.

2) Use different clients. If you cannot use the correct client version, try connecting with a different client version to troubleshoot issues with version compatibility.

3) Reconfigure the Oracle network. If you have tried the above methods and still cannot solve the problem, you can consider reconfiguring the network, including reinstalling the client and rebuilding the TNS service.

4. Summary

Oracle error 12154 is one of the most common errors in the Oracle database. It may be due to an incorrect service name, TNS service configuration problem, IP address or port number. Fill in errors, etc., resulting in the client being unable to connect to the server. The main methods to solve this error include finding the corresponding error source, confirming whether the TNS service is configured correctly, whether the service name is filled in correctly, whether the network connection is normal, whether the Oracle client version is compatible, etc., find out the problem and take corresponding solutions. . When the above method does not work, it is best to try other methods, such as creating a new connection, using a different client, etc. No matter which method is used, we should back up in advance to prevent unexpected events.

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