Query to check the OPTIMAL UNDO RETENTION _____________________________________________________________________________ SELECT d.undo_size / (1024 * 1024) "ACTUAL UNDO SIZE [MByte]", SUBSTR(e.value, 1, 25) "UNDO RETENTION [Sec]", ROUND((d.undo_size / (to_number(f.value) * g.undo_block_per_sec))) "OPTIMAL UNDO RETENTION [Sec]" FROM (SELECT SUM(a.bytes) undo_size FROM v$datafile a, v$tablespace b, dba_tablespaces c WHERE c.contents = 'UNDO' AND c.STATUS = 'ONLINE' AND b.name = c.tablespace_name AND a.ts# = b.ts#) d, v$parameter e, v$parameter f, (SELECT MAX(undoblks / ((end_time - begin_time) * 3600 * 24)) undo_block_per_sec FROM v$undostat) g WHERE e.name = 'undo_retention' AND f.name = 'db_block_size'; ______________________________________________________________________________ tHAN