ORA-20011: Approximate NDV failed: ORA-29913: error in executing ODCIEXTTABLEOPEN callout

*** 2017-02-12 22:08:25.201
DBMS_STATS: GATHER_STATS_JOB: GATHER_TABLE_STATS('"OEM"','"ET$02FEFAAF0001"','""', ...)
DBMS_STATS: ORA-20011: Approximate NDV failed: ORA-29913: error in executing ODCIEXTTABLEOPEN callout
KUP-11024: This external table can only be accessed from within a Data Pump job.

Cause:

1. Temporary Data pump external tables have not been cleaned up properly. The dictionary information should have been dropped when the DataPump jobs completed.

Fix:

set linesize 200 trimspool on
set pagesize 2000
col owner form a30
col created form a25
col last_ddl_time form a25
col object_name form a30
col object_type form a25

select OWNER,OBJECT_NAME,OBJECT_TYPE, status,
to_char(CREATED,'dd-mon-yyyy hh24:mi:ss') created
,to_char(LAST_DDL_TIME , 'dd-mon-yyyy hh24:mi:ss') last_ddl_time
from dba_objects
where object_name like 'ET$%'
/


select owner, TABLE_NAME, DEFAULT_DIRECTORY_NAME, ACCESS_TYPE
from dba_external_tables order by;

And drop the corresponding tables.