简单推一下scn

11g

select name from v$controlfile;
关库，备份控制文件
startup mount pfile=p.ora
col scn for 999999999999999
select CHECKPOINT_CHANGE# scn from v$database;
select file#,change# scn from v$recover_file;
select distinct CHECKPOINT_CHANGE# scn from v$datafile_header;

select to_char(11753987+100*10000,'xxxxxxxxxxxxxxx') scn from dual;

oradebug setmypid
oradebug dumpvar SGA kcsgscn_


ORADEBUG POKE 0x060017E98 8 0xc3b4fa --也可以直接使用10进制，11753987+10000000
alter database open RESETLOGS;

12c之后需要改变方法

*._allow_resetlogs_corruption=true
*.event='21307096 trace name context forever, level 4'

startup mount pfile=i.ora
recover database using backup controlfile until cancel;
alter database open resetlogs;  --level 级别代表400万，这里需要4分钟