ORA-31688: Worker process string failed during startup
Cause: The worker process whose name is listed failed during startup
Action: Refer to any following error messages for possible actions. Check the trace log for the failed process to see if there is any information about the failure. Correct the error, if possible, and try the operation again. If the error occurs again, contact Oracle Customer Support and report the error
https://support.oracle.com/
http://www.oracle.com/