Oracle Error Message
ORA-64149: Invalid alter XMLIndex operation.
Reason for the Error
An attemp was made to alter an XMLIndex that is already being modified using NONBLOCKING ADD_GROUP or ADD_COLUMN. Only NONBLOCKING COMPLETE or ABORT alter index operations are allowed. Also, NONBLOCKING operation is not allowed with alter index rebuild.
Call DBMS_XMLINDEX.PROCESS_PENDING to finish pending work and then execute NONBLOCKING COMPLETE to successfully finish existing NONBLOCKING operation. Execute NONBLOCKING ABORT to cancle existing NONBLOCKING operation.