Oracle connection errors
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The document discusses four common Oracle connection errors: ORA-03113 (end-of-file on communication channel caused by a bug), ORA-12154 (TNS could not resolve connect identifier, check HOST, SERVICE_NAME, and TNSNames.ora file), ORA-12514 (SERVICE value is incorrect, check TNSNames.ora), and ORA-12541 (PORT value is incorrect, try 1521 or 1526). Troubleshooting steps are provided to resolve each error by checking configuration files and values.
Oracle connection errors
- 1. PREPARED BY RAVI KUMAR LANKE Page 1 Oracle Connection Errors The four common connection errors are: ORA-03113:end-of-file on communication channel ORA-12154: TNS: could not resolve the connect identifier specified HOST value incorrect or Global name incorrect or unknown ORA-12514: TNS listener does not currently know of service requested in connect descriptor SERVICE value incorrect ORA-12541: TNS: no listener PORT value incorrect
- 2. PREPARED BY RAVI KUMAR LANKE Page 2 ORA-03113:end-of-file on communication channel ORA-03113 is a catch-all error for any problem interrupting an Oracle session. You may see this error when connecting to Oracle 9.2.0.5. Cause The issue is caused by Oracle bug 3010227. Resolution Ask your Oracle database administrator to apply Oracle patch 9.2.0.6 or to set the Oracle initialization parameter 'STAR_TRANSFORMATION_ENABLED' to FALSE. Other If you would like to test further (this is optional): Step 1 In the Tableau Data window, select Connect to Data. Step 2 In the Connect to Data dialog box, select Oracle, and then click Next.
- 3. PREPARED BY RAVI KUMAR LANKE Page 3 Step 3 In the Oracle Connection dialog box, in the Step 1 text box, type the Oracle connection name. If you are not sure of the syntax of the connection name, click Advanced. Step 4 In the Advanced Oracle Connection dialog box, in their respective boxes, type the Server Name, Service Name, and Port, and then click OK. Step 5 In the Oracle Connection dialog box, under Step 2, provide the Username and Password. Step 6 Under Step 3, click Test Connection. Step 7 When a message box opens to notify you that the connection was successful, click OK. Step 8 Under Step 4, select a schema from the list. Step 9 Under Step 5, select a table or view from the schema, and then select Custom SQL. Step 10 Copy the query that appears in the Step 5 text box. Step 11 In a SQL session connected to this database, paste and run the query. The expected response is error ORA-7445: exception encountered: core dump, which confirms that the problem is ORA-3113, as expected.
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- 5. PREPARED BY RAVI KUMAR LANKE Page 5 ORA-12154: TNS: could not resolve the connect identifier specified Cause ORA-12154 occurs when the transparent network substrate (TNS) cannot resolve the service name. Most often, the SERVICE_NAME or HOST is incorrect. Resolution First, try providing the full database name with the .WORLD extension in the Step 1 text box of the Oracle Connection dialog box. If the full database name doesn't resolve the issue, check the information in the TNSNames.ora file, which is located in your %ORACLE_HOME%networkadmin folder. An example of a TNSNames.ora file is shown here: QAORCL10.world = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = MY_HOST_NAME)(PORT = 1521)) ) (CONNECT_DATA = (SERVICE_NAME = MY_SERVICE_NAME) ) ) The three variables of interest in the file are HOST, PORT, and SERVICE_NAME. Copy these variables from the TNSNames.ora file and keep them available. Note that these variables are case sensitive. To provide these variables for your connection: Step 1
- 6. PREPARED BY RAVI KUMAR LANKE Page 6 In the Tableau Data window, select Connect to Data. Step 2 In the Connect to Data dialog box, select Oracle, and then click Next. Step 3 In the Oracle Connection dialog box, click Advanced. Step 4 In the Advanced Oracle Connection dialog box, in the Server Name text box, provide the HOST name from the TNSNames.ora file. Remember that the variables are case sensitive. Step 5 In the Service Name text box, provide the SERVICE_NAME from the TNSNames.ora file, and in the Port box, provide the PORT number. Step 6 When finished, click OK. Step 7 In the Oracle Connection dialog box, under Step 2, provide the Username and Password. Step 8 Under Step 3, click Test Connection.
- 7. PREPARED BY RAVI KUMAR LANKE Page 7 Step 9 When a message box opens to notify you that the connection was successful, click OK. Step 10 Under Step 4, select a schema from the list. Step 11 Under Step 5, keep the selection of Single Table, and select a table or view from the schema. Step 12 Under Step 6, you have the option to edit the default connection name.
- 8. PREPARED BY RAVI KUMAR LANKE Page 8 Step 13 When finished, click OK.
- 9. PREPARED BY RAVI KUMAR LANKE Page 9 ORA-12514: TNS listener does not currently know of service requested in connect descriptor Cause The SERVICE value is incorrect. Resolution To find out what the correct SERVICE value is, open the TNSNames.ora file located in your %ORACLE_HOME%networkadmin folder. Refer to the steps under ORA_12154 if necessary.
- 10. PREPARED BY RAVI KUMAR LANKE Page 10 ORA-12541: TNS: no listener Cause This error occurs when the PORT value is incorrect. Resolution The PORT is either 1521 or 1526. Try the one not currently in use. Additional Troubleshooting Suggestions If you do not have an Oracle Client installed on your machine, be sure to get the necessary files from your database administrator. If the Oracle data connection errors persist, do the following: Check the TNSNames.ora folder path used to create the TNS_ADMIN variable. Restart your machine to ensure that the TNS_ADMIN variable is recognized. Check that the Oracle connection name used in Tableau exactly matches the TNSNames.ora Net Service Name entry. This name is case sensitive. In some cases Windows will need to be restarted before the Oracle driver will pick up the TNS_ADMIN system variable Contact local IT to verify that the TNSNames.ora file is current. If the Oracle connection uses LDAP, make sure to include the SQLNet.ora file as well as the TNSNames.ora file.