ORA-31468: cannot process DDL change record
Cause: The change set has stop_on_ddl enabled and was trying to process a DDL change record
Action: Check the alert log to find out what the DDL record contained. Make any necessary changes to the change tables. Call ALTER_CHANGE_SET with recover_after_error and remove_ddl set to 'Y'
https://support.oracle.com/
http://www.oracle.com/