This section provides suggested solutions for some common problems related to the use of Connection Manager.
You issue a CMCTL START command to start Connection Manager, and you receive the following messages:
Failed to start service, error 0.
TNS-04002: CMCTL: error while starting the Connection Manager
The Connection Manager Administrator (CMADMIN) has started, but the Connection Manager Gateway (CMGW) has not.
The problem may lie in your cman.ora file. Check the number of parentheses in the address list entry for cman. If the address list can't be parsed because the syntax is incorrect, cman won't start and you'll get an error such as the one shown here.
The Connection Manager Administrator (CMADMIN) process is running by itself and won't shut down when you issue a CMCTL STOP command.
There are two possible solutions for this problem. CMCTL STOP stops both CMADMIN and CMAN, but only if they are both running. If CMADMIN is running by itself, you should be able to stop it using the CMCTL STOP ADM command. If you are running on Windows, another solution is to go to the Services control panel, and stop the CMAdmin service.
Clients have connected via Connection Manager, and the Connection Manager instance has subsequently been aborted. The clients are no longer connected to the database instance, but their connections still show up when you query the V$CIRCUIT view. The sessions are "stuck." Because they count against the maximum number of sessions that you allow for a dispatcher, they are preventing other users from connecting.
Check to see if you have enabled connection pooling. Look for (POOL = YES) in your MTS_DISPATCHERS parameter setting. Try setting (POOL = NO) and see if the problem goes away. When you use connection pooling (i.e., POOL = YES), you should use Oracle's resource limit features to reclaim idle client sessions.