查看SCN

select dbms_flashback.get_system_change_number from dual;

系统检查点SCN：

select CHECKPOINT_CHANGE# from v$database;

数据文件SCN:

select file#,checkpoint_change# from v$datafile;

结束SCN:

select file#,LAST_CHANGE# from v$datafile;

数据文件头SCN:

select file#,CHECKPOINT_CHANGE# from v$datafile_header;

Redo log中的high scn和low scn:

select recid,sequence#,first_change#,next_change# from v$log_history;

currnet redolog中的high scn:

select vf.member,v.status,v.first_change# from v$logfile vf,v$log v where vf.group#=v.group# and v.status='CURRENT';