ORACLE跨越时间点的恢复
在oracle10g之前使用resetlogs打开数据库之后，之前的的备份就不能用于恢复了。即不能进行跨resetlogs时间点的恢复。所以要求执行完之后马上进行全库备份。
Oracle10g以后允许跨越resetlogs时间点进行完全或者不完全恢复。实验如下：
- 执行全库备份。
RMAN> backup database plus archivelog delete all input;
insert into test select * from test;
SQL> alter system switch logfile;
SQL> commit;
Commit complete.
SQL> alter system switch logfile;
System altered.
SQL> truncate table test;
Table truncated.
SQL> alter system switch logfile;
System altered.
SQL> select * from v$log_history;
SQL> select recid,stamp,sequence#,first_change#,first_time,next_change# from v$log_history
2 where recid >80;
RECIDSTAMP FIRST_CHANGE# FIRST_TIME NEXT_CHANGE#
---------- ---------- ------------- ------------ ------------
81 856723148 2130643 27-AUG-14 2130889
82 856752323 2130889 27-AUG-14 2155374
83 856753004 2155375 28-AUG-14 2175380
84 856753636 2175380 28-AUG-14 2176030
85 856754916 2176030 28-AUG-14 2177334
86 856754945 2177334 28-AUG-14 2177347
87 856755046 2177347 28-AUG-14 2178414
88 856755142 2178414 28-AUG-14 2178471
89 856755199 2178471 28-AUG-14 2178508
90 856755243 2178508 28-AUG-14 2178543
91 856755424 2178543 28-AUG-14 2178823
RECIDSTAMP FIRST_CHANGE# FIRST_TIME NEXT_CHANGE#
---------- ---------- ------------- ------------ ------------
92 856755456 2178823 28-AUG-14 2178836
93 856755483 2178836 28-AUG-14 2178940
13 rows selected.
- 关闭数据库、删除数据模拟故障
删除之后，执行如下
RMAN> startup mount;
Oracle instance started
database mounted
Total System Global Area 599785472 bytes
Fixed Size 2022600 bytes
Variable Size 268436280 bytes
Database Buffers 322961408 bytes
Redo Buffers 6365184 bytes
RMAN> run{
set until sequence 12 thread 1;
restore database;
recover database;
}
这里判断具体到那个sequence，当前查询如下，历史查看v$log_history的sequence#：
Sql>archive log list;
如果出现这个错误：
SQL> recover database until cancel;
ORA-00283: recovery session canceled due to errors
ORA-01610: recovery using the BACKUP CONTROLFILE option must be done
SQL> recover database BACKUP CONTROLFILE
ORA-00905: missing keyword
解决：
recover database using backup controlfile until cancel;
RMAN> alter database open resetlogs;
查看序号是否复位：
SQL> archive log list;
Database log mode Archive Mode
Automatic archival Enabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 0
Next log sequence to archive 1
Current log sequence 1
SQL> create conn xzsp create tt able tt as select * from dba_users;
Table created.
SQL> alter system switch logfile;
System altered.
SQL> select count(*) from tt;
COUNT(*)
----------
26
SQL> inert in sert into tt select * from tt;
26 rows created.
SQL> /
52 rows created.
SQL> /
104 rows created.
SQL> commit
2 ;
Commit complete.
SQL> alter system switch logfile;
System altered.
SQL> select recid,stamp,first_change#,first_time,next_change# from v$log_history;
RECID STAMP SEQUENCE# FIRST_CHANGE# FIRST_TIME NEXT_CHANGE#
---------- ---------- ---------- ------------- ------------ ------------
100 856759449 1 2179277 28-AUG-14 2179707
101 856759476 2 2179707 28-AUG-14 2179788
102 856761071 1 2179621 28-AUG-14 2179920
103 856761108 2 2179920 28-AUG-14 2179945
103 rows selected.
Oracle保留了resetlogs之前的日志序列号，并且日志recid继续增长，控制文件也保留了归档日志的序列。所以可以跨RESETLOGS进行恢复。10g以前 是不能够使用当前控制文件恢复之前的备份的。
RMAN> run {
2> restore database;
3> recover database;
4> }
SQL> select count(*) from tt;
COUNT(*)
----------
208
恢复能够完成，还有log_archive_format有关系。
Sql>show parameter log_archive_format
log_archive_format string archive_%t_%s_%r.log
这里的%R是oracle新增的参数,是resetlogs的标志号.这一归档日志格式可以是不同Incarnation的数据库归档日志避免相互覆盖，从而跨越resetlogs恢复的日志基础得以保证。
思考：这里看到rman备份只有一次，是在resetlogs之前，第二次完全恢复是基于之前的备份。这里看到oracle10确实是越过了resetlog执行了恢复。
