基于序列号 （sequence number）
做不完全恢复之前，要给数据库做一个备份 这里用rman 做

sequence number是指 redo log的序列号

SQL> create table scott.test1(n1 number);
SQL> insert into scott.test1 values(1); 
SQL> insert into scott.test1 values(2); 
SQL> commit;                            
SQL> alter system switch logfile;       
SQL> insert into scott.test1 values(3); 
SQL> insert into scott.test1 values(4); 
SQL> commit;                            
SQL> select * from v$log;               
                                                                                                          

  
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIME
----- ------- ---------- ----- ------- --- ------ ------------- ----------
1      1       11        104857600   1 NO  CURRENT  305030 2007-12-03:18:39:21
2      1        9        104857600   1 YES INACTIVE 284753 2007-12-03:18:09:52
3      1       10        104857600   1 YES ACTIVE   304755 2007-12-03:18:17:49
SQL> shutdown abort
1号组为当前组，将其破坏
SQL> startup mount

RUN {
    SET UNTIL SEQUENCE 11 THREAD 1;
    RESTORE DATABASE; 
    RECOVER DATABASE;
    ALTER DATABASE OPEN RESESTLOGS;}
   
   
SQL> select * from scott.test1
  2  /                       
                             
        N1                   
----------                   
         1                   
         2                   
scott.test1 中3,4没有归档，丢失