alter database open resetlogs
問題解決:
先要弄清楚alter database open resetlogs是什么意思,為什么要用resetlogs打開數據庫,這個命令發出后oracle都做了什么?
alter database open resetlogs是要打開數據時,重置重做日志,即將重做日志的sequence置零,為什么要重置重做日志呢?
不完全恢復后,原來的online redo log里面包含的是未做恢復前的數據,而這些數據對于恢復后的數據庫不再有效,所以數據庫會要求在Open之前先對online redo log的sequence置零。
Resetlogs命令表示一個數據庫邏輯生存期的結束和另一個數據庫邏輯生存期的開始,每次使用Resetlogs命令的時候,SCN不會被重置,不過oracle會重置日志序列號,而且會重置聯機重做日志內容。
Oracle把這個數據庫邏輯生存期稱為incarnation
每次使用resetlogs打開數據庫,就會使incarnation + 1,也就是產生一個新的incarnation;
如果想要恢復到之前incarnation的scn/time,就需要先恢復到之前的incarnation;
對于上面的案例,具體就是先要
Reset database to incarnation 2;
再做不完全恢復試試
--------------------------我執行一次rman之后,再次執行這個腳本--------------
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http://hi.baidu.com/heuet032606/item/4553f3c1d8f8b22c47d5c07c
http://blog.csdn.net/leishifei/article/details/6430057
關于alter database open resetlogs及incarnation的一點理解
不完全恢復只能做一次嗎?
采用rman的默認設置,對數據庫進行了backup database備份,進行了一些操作后,然后直接關閉啟動到mount狀態
RMAN> run{
2> set until time "to_date('2010-10-16 23:14:42','yyyy-mm-dd hh24:mi:ss')";
3> restore database;
4> recover database;
5> }
executing command: SET until clause
Starting restore at 17-OCT-10
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=156 devtype=DISK
channel ORA_DISK_1: starting datafile backupset restore
channel ORA_DISK_1: specifying datafile(s) to restore from backup set
restoring datafile 00001 to /oracle/oradata/denver/system01.dbf
restoring datafile 00002 to /oracle/oradata/denver/undotbs01.dbf
restoring datafile 00003 to /oracle/oradata/denver/sysaux01.dbf
restoring datafile 00004 to /oracle/oradata/denver/users01.dbf
restoring datafile 00005 to /oracle/oradata/denver/example01.dbf
channel ORA_DISK_1: reading from backup piece /oracle/flash_recovery_area/DENVER/backupset/2010_10_16/o1_mf_nnndf_TAG20101016T230845_6cmhzz8t_.bkp
channel ORA_DISK_1: restored backup piece 1
piece handle=/oracle/flash_recovery_area/DENVER/backupset/2010_10_16/o1_mf_nnndf_TAG20101016T230845_6cmhzz8t_.bkp tag=TAG20101016T230845
channel ORA_DISK_1: restore complete, elapsed time: 00:01:26
Finished restore at 17-OCT-10
Starting recover at 17-OCT-10
using channel ORA_DISK_1
starting media recovery
archive log thread 1 sequence 10 is already on disk as file /oracle/archivelog/1_10_732510268.dbf
archive log filename=/oracle/archivelog/1_10_732510268.dbf thread=1 sequence=10
media recovery complete, elapsed time: 00:00:01
Finished recover at 17-OCT-10
RMAN> alter database open resetlogs;
database opened
發現剛才恢復的時間23:14:42有點早,于是想改為恢復時間點為23:17:26,于是再次關閉數據庫,mount狀態下,但是出錯了
RMAN> run {
2> set until time "to_date('2010-10-16 23:17:26','yyyy-mm-dd hh24:mi:ss')";
3> restore database;
4> recover database;
5> }
executing command: SET until clause
using target database control file instead of recovery catalog
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of set command at 10/17/2010 00:45:40
RMAN-20207: UNTIL TIME or RECOVERY WINDOW is before RESETLOGS time
時間再前點恢復也不行:
RMAN> run {
2> set until time "to_date('2010-10-16 23:14:40','yyyy-mm-dd hh24:mi:ss')";
3> restore database;
4> recover database;
5> }
executing command: SET until clause
using target database control file instead of recovery catalog
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of set command at 10/17/2010 01:17:03
RMAN-20207: UNTIL TIME or RECOVERY WINDOW is before RESETLOGS time
這是為什么?那些歸檔都還在,難道我的rman做過一次不完全恢復后,就不能再不完全恢復了,跟有沒有換備份控制文件有關系嗎?里面做了什么呢?
RMAN> list incarnation;
using target database control file instead of recovery catalog
List of Database Incarnations
DB Key? Inc Key DB Name? DB ID????????? ? STATUS? Reset SCN? Reset Time
------- ------- -------- ---------------- --- ---------- ----------
1???? ? 1???? ? DENVER ? 4021391415???? ? PARENT? 1??????? ? 22-OCT-05
2???? ? 2???? ? DENVER ? 4021391415???? ? PARENT? 525876?? ? 16-OCT-10
3???? ? 3???? ? DENVER ? 4021391415???? ? CURRENT 620239?? ? 17-OCT-10
問題解決:
先要弄清楚alter database open resetlogs是什么意思,為什么要用resetlogs打開數據庫,這個命令發出后oracle都做了什么?
alter database open resetlogs是要打開數據時,重置重做日志,即將重做日志的sequence置零,為什么要重置重做日志呢?
不完全恢復后,原來的online redo log里面包含的是未做恢復前的數據,而這些數據對于恢復后的數據庫不再有效,所以數據庫會要求在Open之前先對online redo log的sequence置零。
Resetlogs命令表示一個數據庫邏輯生存期的結束和另一個數據庫邏輯生存期的開始,每次使用Resetlogs命令的時候,SCN不會被重置,不過oracle會重置日志序列號,而且會重置聯機重做日志內容。
Oracle把這個數據庫邏輯生存期稱為incarnation
每次使用resetlogs打開數據庫,就會使incarnation + 1,也就是產生一個新的incarnation;
如果想要恢復到之前incarnation的scn/time,就需要先恢復到之前的incarnation;
對于上面的案例,具體就是先要
Reset database to incarnation 2;
再做不完全恢復試試
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