基于cancel 的不一致性恢复（归档丢失） 第二篇
主要适用于：基于Cancel的不完全恢复适用场景：Recover时，所需的某个归档日志损坏，或主机断电，current状态的联机日志损坏。
创建测试表
创建wwl002表，切换日志，再创建新的wwl003表，主机断电，删除当前日志，模拟文件损坏。
SQL> conn wwl/wwl
Connected.
SQL> select * from tab;
TNAME TABTYPE CLUSTERID
------------------------------ -----------------
WWL001 TABLE
SQL> create table WWL002 as select *from wwl001;
Table created.
SQL> conn / as sysdba
Connected.
切换日志
SQL> alter system switch logfile;
System altered.
后再创建第二张表
SQL> conn wwl/wwl
Connected.
SQL> create table wwl003 as select *from wwl001;
Table created.
查看当前日志组，确定当前活动的日志组，是组4
SQL> conn / as sysdba
Connected.
SQL> set line 200
SQL> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- -------------------- --- ---------------- ------------- ---------
4 1 2 134217728 2 YES ACTIVE 1716929 30-JUL-12
5 1 1 134217728 2 YES INACTIVE 1692728 27-JUL-12
6 1 3 134217728 2 NO CURRENT 1720396 30-JUL-12
7 1 0 134217728 2 YES UNUSED 0
定位当前日志组的日志文件，有两个。
SQL> col member format a30
SQL> select * from v$logfile;
GROUP# STATUS TYPE MEMBER IS_
---------- ------- ------------------------------------- ---
7 ONLINE /DBBak2/oradata/WWL/redo7a.log NO
7 ONLINE /DBBak2/oradata/WWL/redo7b.log NO
6 ONLINE /DBBak2/oradata/WWL/redo6a.log NO
6 ONLINE /DBBak2/oradata/WWL/redo6b.log NO
5 STALE ONLINE /DBBak2/oradata/WWL/redo5a.log NO
5 STALE ONLINE /DBBak2/oradata/WWL/redo5b.log NO
4 ONLINE /DBBak2/oradata/WWL/redo4a.log NO
4 ONLINE /DBBak2/oradata/WWL/redo4b.log NO
8 rows selected.
删除当前日志组文件，模拟在线事务丢失：
SQL> !rm -f/DBBak2/oradata/WWL/redo4a.log
SQL> !rm -f/DBBak2/oradata/WWL/redo4b.log
模拟服务器断电
SQL> shutdown abort;
恢复步骤:
1、尝试启动数据库的时候报当前日志丢失。
SQL> startup
ORACLE instance started.
Total System Global Area 100663296 bytes
Fixed Size 1217884 bytes
Variable Size 88083108 bytes
Database Buffers 8388608 bytes
Redo Buffers 2973696 bytes
Database mounted.
ORA-00313: open failedfor members of log group 4 of thread 1
ORA-00312: online log 4thread 1: '/DBBak2/oradata/WWL/redo4b.log'
ORA-27037: unable toobtain file status
Linux Error: 2: No suchfile or directory
Additional information: 3
ORA-00312: online log 4thread 1: '/DBBak2/oradata/WWL/redo4a.log'
ORA-27037: unable toobtain file status
Linux Error: 2: No suchfile or directory
Additional information: 3
2、尝试Clear redo4
SQL> alter database clear logfile group4;
alter database clear logfile group 4
*
ERROR at line 1:
ORA-01624: log 4 needed for crash recoveryof instance WWL (thread 1)
ORA-00312: online log 4 thread 1:'/DBBak2/oradata/WWL/redo4a.log'
ORA-00312: online log 4 thread 1:'/DBBak2/oradata/WWL/redo4b.log'
3、在当前库做基于Cancel的不完全恢复
SQL> recover database until cancel;
ORA-00279: change 1716930 generated at07/30/2012 11:03:51 needed for thread 1
ORA-00289: suggestion :/DBSoft/product/10.2.0/db_1/dbs/arch1_2_