ORA-28545 Oracle to MySQL Connection Error Tips

Question:  I am trying to connect Oracle to MySQL using heterogeneous services and I get this error:

Link : "DG4ODBC.UOU.EDU.PS"
Error : ORA-28545: error diagnosed by Net8 when connecting to an agent
Unable to retrieve text of NETWORK/NCR message 65535
ORA-02063: preceding 2 lines from DG4ODBC

How do I fix this ORA-28545 error?

Answer:  This can be a listener syntax error or a generic connectivity issue.  Review the steps to connect Oracle to MySQL  carefully:

• Set global_names=false

•  Verify that the standard ODBC connection to MySQL works

•  Verify that you can connect via the standard database link.  Make sure that the listener name points to the heterogeneous services link.

•  Check the listener.ora syntax as this can be a listener.ora syntax problem:

1.  Make sure that your $ORACLE_HOME is correct
2. Make sure that you can the host name (and not the IP address) for the servers.  

There are several other solutions for a ORA-28545 error:

•  Please see MOSC note: 264567.1 titled "How to setup Generic Connectivity HSODBC on Linux".  Please note that heterogeneous services only works on 32 bit servers, not 64 bit itanium . . .

•  Also see MOSC note 364369.1.  You may need to apply the 10.2.02 CPU . . .

The oerr message output for the ORA-28545 says that the database link connection failed:  

ORA-28545: error diagnosed by Net8 when connecting to an agent  

Cause: An attempt to call an external procedure or to issue SQL to a non-Oracle system on a Heterogeneous Services database link failed at connection initialization. The error diagnosed by Net8 NCR software is reported separately.  

Action: Refer to the Net8 NCRO error message. If this isn't clear, check connection administrative setup in tnsnames.ora and listener.ora for the service associated with the Heterogeneous Services database link being used, or with 'extproc_connection_data' for an external procedure call.  

See these steps for diagnosing the ORA-28545 error:  

1. Install Oracle ODBC drivers on the server (your local Oracle database) that will access the remote MySQL database using the database link.  
2. Setup the ODBC connection on the local Oracle database  
3. Test the ODBC drivers to ensure that connectivity is made to the MySQL database.  
4. Ensure that your global_names parameter is set to False.  
5. Configure the Oracle Heterogeneous services by creating an initodbc.ora file within the Oracle database.  
6. Modify the Listener.ora file:
     
   SID_NAME is the DSN for the remote database.
   ORACLE_HOME is the actual Oracle home file path.
   PROGRAM tells Oracle to use heterogeneous services.
   
   SID_LIST_LISTENER =
   (SID_LIST =
   (SID_DESC =
   (SID_NAME=Cas30C) -- Enter the DSN on this line
   (ORACLE_HOME = c:\oracle10gdb) -- Enter your Oracle home on this line
   (PROGRAM = hsodbc) ) )  
     
7. Modify the Tnsnames.ora file: This is the Oracle database installation accessed by the users to connect to the ODBC drivers.
   
   (DESCRIPTION=
   (ADDRESS_LIST= (
   Address=(PROTOCOL=TCP) (HOST=
   -- (Server x) (PORT=1521))) -- Enter the port on which the server x Oracle installation -- is listening
   (CONNECT_DATA=(SID=Cas30c)) - Enter the DSN name
   (HS=OK) -- Enter this value. It tells Oracle to use hetergeneous services )
     
8. Reload the listener on local Oracle database.  
9. Create a database link on the local Oracle installation that accesses the heterogeneous connection, which, in turn, connect to MySQL.  
10.  Run a MySQL "select" SQL statement from the Oracle installation using the database link.  

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