转自崔华的<<基于ORACLE的sql优化>>

SET LINES 300
alter session set nls_timestamp_tz_format='YYYY-MM-DD HH24:MI:SS';
alter session set nls_date_format='YYYY-MM-DD HH24:MI:SS';
select savtime,rowcnt,blkcnt,avgrln,analyzetime from sys.wri$_optstat_tab_history where obj#='123';