oracle ora 00283,【案例】Oracle报错ORA-16433非归档丢失redo无法启动的恢复过程
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Oracle研究中心案例分析：運(yùn)維DBA反映Oracle數(shù)據(jù)庫(kù)處理非歸檔模式，redo文件損壞常規(guī)修復(fù)無(wú)法正常open數(shù)據(jù)庫(kù)。
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本文鏈接地址: One recover case!
今天ML的群中女神和travel在糾結(jié)一個(gè)恢復(fù)的問(wèn)題，11.2.0.3版本，非歸檔，大概是rm掉current的log，然后重建controlfille后恢復(fù)導(dǎo)致一系列問(wèn)題，并最終出現(xiàn)ora-600 2662錯(cuò)誤，雖然這個(gè)錯(cuò)誤很常見(jiàn)，但是你發(fā)現(xiàn)推進(jìn)scn也是無(wú)法open，感覺(jué)有點(diǎn)怪，遠(yuǎn)程了女神的電腦，操作不便，最后將文件壓縮傳過(guò)來(lái)，我在自己的vmware進(jìn)行了恢復(fù)。
由于環(huán)境的差異，所以解壓后我先進(jìn)行rename file操作，如下：
SQL> SELECT name FROM v$datafile;
NAME
------------------------------------------------
/u01/app/oracle/oradata/travel/system01.dbf
.........
/u01/app/oracle/oradata/travel/users01.dbf
SQL> SELECT member FROM v$logfile;
MEMBER
-------------------------------------------------
/u01/app/oracle/oradata/travel/redo03.log
/u01/app/oracle/oradata/travel/redo02.log
/u01/app/oracle/oradata/travel/redo01.log
SQL> ALTER DATABASE RENAME file '/u01/app/oracle/oradata/travel/system01.dbf' TO '/home/oracle/travel/travel/system01.dbf';
SQL>? ALTER DATABASE RENAME file '/u01/app/oracle/oradata/travel/sysaux01.dbf' TO '/home/oracle/travel/travel/sysaux01.dbf';
SQL>? ALTER DATABASE RENAME file '/u01/app/oracle/oradata/travel/undotbs01.dbf' TO '/home/oracle/travel/travel/undotbs01.dbf';
SQL> ALTER DATABASE RENAME file '/u01/app/oracle/oradata/travel/users01.dbf' TO '/home/oracle/travel/travel/users01.dbf';
SQL> ALTER DATABASE RENAME file '/u01/app/oracle/oradata/travel/redo01.log' TO '/home/oracle/travel/travel/redo01.log';
SQL> ALTER DATABASE RENAME file '/u01/app/oracle/oradata/travel/redo02.log' TO '/home/oracle/travel/travel/redo02.log';
SQL> ALTER DATABASE RENAME file '/u01/app/oracle/oradata/travel/redo03.log' TO '/home/oracle/travel/travel/redo03.log';
SQL> SELECT name FROM v$datafile;
NAME
-------------------------------------------------
/home/oracle/travel/travel/system01.dbf
/home/oracle/travel/travel/sysaux01.dbf
/home/oracle/travel/travel/undotbs01.dbf
/home/oracle/travel/travel/users01.dbf
SQL> SELECT member FROM v$Logfile;
MEMBER
-------------------------------------------------
/home/oracle/travel/travel/redo03.log
/home/oracle/travel/travel/redo02.log
/home/oracle/travel/travel/redo01.log
此時(shí),進(jìn)行recover，會(huì)報(bào)錯(cuò)ORA-16433，如下：
SQL> recover DATABASE;
ORA-00283: recovery SESSION canceled due TO errors
ORA-16433: The DATABASE must be opened IN READ/WRITE mode.
SQL> recover DATABASE USING backup controlfile until cancel;
ORA-00283: recovery SESSION canceled due TO errors
ORA-16433: The DATABASE must be opened IN READ/WRITE mode.
SQL> ALTER DATABASE OPEN;
ALTER DATABASE OPEN
*
ERROR at line 1:
ORA-01113: file 1 needs media recovery
ORA-01110: DATA file 1: '/home/oracle/travel/travel/system01.dbf'
關(guān)于該錯(cuò)誤，通過(guò)oerr命令可以大概了解一下其含義，如下：
[oracle@11gR2_primary ~]$ oerr ora 16433
16433, 00000, "The database must be opened in read/write mode."
// *Cause:? An attempt was made to open the database in read-only mode after an
//????????? operation that requires that the database be opened in read/write
//????????? mode.
// *Action: Open the database in read/write mode. The database can then be
//????????? opened in read-only mode.
通過(guò)這個(gè)錯(cuò)誤，我們可以得出一個(gè)信息，數(shù)據(jù)庫(kù)可以以read only模式打開(kāi)，換句話講，你查詢?nèi)缦聨讉€(gè)值都是一樣的：
select checkpoint_change# from v$database;?? --來(lái)自controlfile
select checkpoint_change# from v$datafile;?? --來(lái)自controlfile
select checkpoint_change# from v$datafile_orader;? --來(lái)自datafile header
其實(shí)，通常來(lái)講，只要上述幾個(gè)值一樣，那么我們的db應(yīng)該都是可以直接open打開(kāi)的，然而，這里卻不行，read only都不行，我試過(guò)。
然后下面就開(kāi)始我的恢復(fù)工作。
第一次嘗試恢復(fù)：
---重建controlfile
SQL> startup nomount? pfile=/home/oracle/travel/travel/a.ora
ORACLE instance started.
Total System Global Area? 626327552 bytes
Fixed Size????????????????? 2230952 bytes
Variable Size???????????? 184550744 bytes
Database Buffers????????? 436207616 bytes
Redo Buffers??????????????? 3338240 bytes
SQL> CREATE CONTROLFILE REUSE DATABASE "TRAVEL" RESETLOGS? NOARCHIVELOG
2????? MAXLOGFILES 16
3????? MAXLOGMEMBERS 3
4????? MAXDATAFILES 100
5????? MAXINSTANCES 8
6????? MAXLOGHISTORY 292
7? LOGFILE
8??? GROUP 1 '/home/oracle/travel/travel/redo01.log'? SIZE 50M BLOCKSIZE 512,
9??? GROUP 2 '/home/oracle/travel/travel/redo02.log'? SIZE 50M BLOCKSIZE 512,
10??? GROUP 3 '/home/oracle/travel/travel/redo03.log'? SIZE 50M BLOCKSIZE 512
11? -- STANDBY LOGFILE
12? DATAFILE
13??? '/home/oracle/travel/travel/system01.dbf',
14??? '/home/oracle/travel/travel/sysaux01.dbf',
15??? '/home/oracle/travel/travel/undotbs01.dbf',
16??? '/home/oracle/travel/travel/users01.dbf'
17? CHARACTER SET AL32UTF8
18? ;
Control file created.
SQL>
開(kāi)始開(kāi)始進(jìn)行recover：
SQL> alter database open resetlogs;
alter database open resetlogs
*
ERROR at line 1:
ORA-01194: file 1 needs more recovery to be consistent
ORA-01110: data file 1: '/home/oracle/travel/travel/system01.dbf'
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 using backup controlfile until cancel;
ORA-00279: change 244977 generated at 01/19/2013 01:56:54 needed for thread 1
ORA-00289: suggestion : /oracle/product/11.2.0/db_1/dbs/arch1_1_805082211.dbf
ORA-00280: change 244977 for thread 1 is in sequence #1
Specify log: {=suggested | filename | AUTO | CANCEL}
cancel
ORA-01547: warning: RECOVER succeeded but OPEN RESETLOGS would get error below
ORA-01194: file 1 needs more recovery to be consistent
ORA-01110: data file 1: '/home/oracle/travel/travel/system01.dbf'
ORA-01112: media recovery not started
因?yàn)楸旧硎欠菤w檔，所以這個(gè)不完全恢復(fù)的步驟無(wú)非是為了后面可以進(jìn)行open resetlog。然后停庫(kù)，加入隱含參數(shù)進(jìn)行open：
SQL> shutdown immediate
ORA-01109: DATABASE NOT OPEN
DATABASE dismounted.
ORACLE instance shut down.
SQL> startup nomount? pfile=/home/oracle/travel/travel/b.ora
ORACLE instance started.
Total System Global Area? 626327552 bytes
Fixed SIZE????????????????? 2230952 bytes
Variable SIZE???????????? 184550744 bytes
DATABASE Buffers????????? 436207616 bytes
Redo Buffers??????????????? 3338240 bytes
SQL> ALTER DATABASE mount
DATABASE altered.
SQL> ALTER DATABASE OPEN resetlogs;
ALTER DATABASE OPEN resetlogs
*
ERROR at line 1:
ORA-01092: ORACLE instance TERMINATED. Disconnection forced
ORA-00600: internal error code, arguments: [2662], [0], [244985], [0],
[244998], [4194432], [], [], [], [], [], []
Process ID: 3641
SESSION ID: 1 Serial NUMBER: 5
此時(shí)alert log對(duì)應(yīng)的錯(cuò)誤如下：
Fri Dec 14 21:58:39 2012
SMON: enabling cache recovery
Errors in file /oracle/diag/diag/rdbms/travel/travel/trace/travel_ora_3641.trc? (incident=4937):
ORA-00600: internal error code, arguments: [2662], [0], [244985], [0], [244998], [4194432], [], [], [], [], [], []
Incident details in: /oracle/diag/diag/rdbms/travel/travel/incident/incdir_4937/travel_ora_3641_i4937.trc
Fri Dec 14 21:58:43 2012
Dumping diagnostic data in directory=[cdmp_20121214215843], requested by (instance=1, osid=3641), summary=[incident=4937].
Use ADRCI or Support Workbench to package the incident.
See Note 411.1 at My Oracle Support for error and packaging details.
Errors in file /oracle/diag/diag/rdbms/travel/travel/trace/travel_ora_3641.trc:
ORA-00600: internal error code, arguments: [2662], [0], [244985], [0], [244998], [4194432], [], [], [], [], [], []
Errors in file /oracle/diag/diag/rdbms/travel/travel/trace/travel_ora_3641.trc:
ORA-00600: internal error code, arguments: [2662], [0], [244985], [0], [244998], [4194432], [], [], [], [], [], []
Error 600 happened during db open, shutting down database
USER (ospid: 3641): terminating the instance due to error 600
Instance terminated by USER, pid = 3641
ORA-1092 signalled during: alter database open resetlogs...
opiodr aborting process unknown ospid (3641) as a result of ORA-1092
甚至手工執(zhí)行如下操作都無(wú)法open數(shù)據(jù)庫(kù)，如下：
SQL> ALTER SESSION SET events '10015 trace name ADJUST_SCN level 14';
SESSION altered.
SQL> ALTER DATABASE OPEN;
ALTER DATABASE OPEN
*
ERROR at line 1:
ORA-01113: file 1 needs media recovery
ORA-01110: DATA file 1: '/home/oracle/travel/travel/system01.dbf'
最后dunmp controlfile和CURRENT redo logfile，發(fā)現(xiàn)low cache rba信息居然是最大值：
SQL> oradebug setmypid
Statement processed.
SQL> ALTER system? SET events 'immediate trace name controlf level 4'?? ;
System altered.
SQL> ALTER system? dump logfile '/home/oracle/travel/travel/redo01.log';
SQL> oradebug tracefile_name
/oracle/diag/diag/rdbms/travel/travel/trace/travel_ora_4229.trc
++++++++ controlfile dump 片段
***************************************************************************
CHECKPOINT PROGRESS RECORDS
***************************************************************************
(size = 8180, compat size = 8180, section max = 11, section in-use = 0,
last-recid= 0, old-recno = 0, last-recno = 0)
(extent = 1, blkno = 2, numrecs = 11)
THREAD #1 - status:0x2 flags:0x0 dirty:0
low cache rba:(0xffffffff.ffffffff.ffff) on disk rba:(0x1.3.0)? ---low cache rba為無(wú)窮大
on disk scn: 0x0000.0003bcf7 12/14/2012 21:58:39
resetlogs scn: 0x0000.0003bcf2 12/14/2012 21:58:36
heartbeat: 802069494 mount id: 2869233386
THREAD #2 - status:0x0 flags:0x0 dirty:0
low cache rba:(0x0.0.0) on disk rba:(0x0.0.0)
on disk scn: 0x0000.00000000 01/01/1988 00:00:00
resetlogs scn: 0x0000.00000000 01/01/1988 00:00:00
heartbeat: 0 mount id: 0
THREAD #3 - status:0x0 flags:0x0 dirty:0
low cache rba:(0x0.0.0) on disk rba:(0x0.0.0)
on disk scn: 0x0000.00000000 01/01/1988 00:00:00
resetlogs scn: 0x0000.00000000 01/01/1988 00:00:00
heartbeat: 0 mount id: 0
+++++++redo01.log dump 片段
DUMP OF REDO FROM FILE '/home/oracle/travel/travel/redo01.log'
Opcodes *.*
RBAs: 0x000000.00000000.0000 thru 0xffffffff.ffffffff.ffff
SCNs: scn: 0x0000.00000000 thru scn: 0xffff.ffffffff
Times: creation thru eternity
FILE HEADER:
Compatibility Vsn = 186646528=0xb200000
Db ID=2872261344=0xab333ae0, Db Name='TRAVEL'
Activation ID=2872292516=0xab33b4a4
Control Seq=233=0xe9, File size=102400=0x19000
File Number=1, Blksiz=512, File Type=2 LOG
descrip:"Thread 0001, Seq# 0000000001, SCN 0x00000003bcee-0xffffffffffff"
thread: 1 nab: 0xffffffff seq: 0x00000001 hws: 0x3 eot: 1 dis: 0
resetlogs count: 0x2ffc9463 scn: 0x0000.0003bcee (244974)
prev resetlogs count: 0x2ffc7a41 scn: 0x0000.0003bcea (244970)
Low? scn: 0x0000.0003bcee (244974) 01/19/2013 01:56:51
Next scn: 0xffff.ffffffff 01/01/1988 00:00:00
Enabled scn: 0x0000.0003bcee (244974) 01/19/2013 01:56:51
Thread closed scn: 0x0000.0003bcee (244974) 01/19/2013 01:56:51
Disk cksum: 0x3467 Calc cksum: 0x3467
Terminal recovery stop scn: 0x0000.00000000
Terminal recovery? 01/01/1988 00:00:00
Most recent redo scn: 0x0000.00000000
Largest LWN: 0 blocks
End-of-redo stream : No
Unprotected mode
Miscellaneous flags: 0x800000
Thread internal enable indicator: thr: 0, seq: 0 scn: 0x0000.00000000
Zero blocks: 0
Format ID is 2
redo log key is 853c461da2eec7ed4b45ce75b8c27d7
redo log key flag is 5
Enabled redo threads: 1
REDO RECORD - Thread:1 RBA: 0x000001.00000002.0010 LEN: 0x0070 VLD: 0x05
SCN: 0x0000.0003bcf2 SUBSCN:? 1 01/19/2013 01:56:54
(LWN RBA: 0x000001.00000002.0010 LEN: 0001 NST: 0001 SCN: 0x0000.0003bcee)? ，
CHANGE #1 MEDIA RECOVERY MARKER SCN:0x0000.00000000 SEQ:0 OP:17.3 ENC:0
END OF REDO DUMP
可以看到實(shí)際上current redo的LWN RBA是對(duì)的，為1.2.10，是小于on disk rba (0×1.3.0)的。那么這里為什么會(huì)出現(xiàn)這個(gè)情況？
猜測(cè)可能是寫(xiě)紊亂了。到這里也就比較明白了，仍然是conrolfile有問(wèn)題。
既然如此，那么我直接將controlfile文件rm掉，然后再次重建。如下：
SQL> startup nomount pfile='/home/oracle/travel/travel/a.ora
ORACLE instance started.
Total System Global Area? 626327552 bytes
Fixed Size????????????????? 2230952 bytes
Variable Size???????????? 184550744 bytes
Database Buffers????????? 436207616 bytes
Redo Buffers??????????????? 3338240 bytes
SQL> CREATE CONTROLFILE REUSE DATABASE "TRAVEL" RESETLOGS? NOARCHIVELOG
2????? MAXLOGFILES 16
3????? MAXLOGMEMBERS 3
4????? MAXDATAFILES 100
5????? MAXINSTANCES 8
6????? MAXLOGHISTORY 292
7? LOGFILE
8??? GROUP 1 '/home/oracle/travel/travel/redo01.log'? SIZE 50M BLOCKSIZE 512,
9??? GROUP 2 '/home/oracle/travel/travel/redo02.log'? SIZE 50M BLOCKSIZE 512,
10??? GROUP 3 '/home/oracle/travel/travel/redo03.log'? SIZE 50M BLOCKSIZE 512
11? -- STANDBY LOGFILE
12? DATAFILE
13??? '/home/oracle/travel/travel/system01.dbf',
14??? '/home/oracle/travel/travel/sysaux01.dbf',
15??? '/home/oracle/travel/travel/undotbs01.dbf',
16??? '/home/oracle/travel/travel/users01.dbf'
17? CHARACTER SET AL32UTF8
18? ;
Control file created.
SQL> recover database until cancel using backup controlfile;
ORA-00279: change 244985 generated at 12/14/2012 23:05:06 needed for thread 1
ORA-00289: suggestion : /oracle/product/11.2.0/db_1/dbs/arch1_1_802047904.dbf
ORA-00280: change 244985 for thread 1 is in sequence #1
Specify log: {=suggested | filename | AUTO | CANCEL}
AUTO
ORA-00308: cannot open archived log
'/oracle/product/11.2.0/db_1/dbs/arch1_1_802047904.dbf'
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
ORA-00308: cannot open archived log
'/oracle/product/11.2.0/db_1/dbs/arch1_1_802047904.dbf'
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
ORA-01547: warning: RECOVER succeeded but OPEN RESETLOGS would get error below
ORA-01194: file 1 needs more recovery to be consistent
ORA-01110: data file 1: '/home/oracle/travel/travel/system01.dbf'
SQL>
SQL>
SQL> select file#,CHECKPOINT_CHANGE#,LAST_CHANGE# from v$datafile order by? 1;
FILE# CHECKPOINT_CHANGE# LAST_CHANGE#
---------- ------------------ ------------
1???????????? 244985
2???????????? 244985
3???????????? 244985
4???????????? 244985
SQL> select file#,CHECKPOINT_CHANGE# from v$datafile_header order by 1;
FILE# CHECKPOINT_CHANGE#
---------- ------------------
1???????????? 244985
2???????????? 244985
3???????????? 244985
4???????????? 244985
SQL> select CHECKPOINT_CHANGE# from v$database;
CHECKPOINT_CHANGE#
------------------
0
此時(shí)停庫(kù)，然后在pfile中加入隱含參數(shù)：
*._allow_resetlogs_corruption=TRUE
*._allow_error_simulation=TRUE
接著再次進(jìn)行mount，并進(jìn)行scn 推進(jìn)：
SQL> ALTER DATABASE OPEN resetlogs;
ALTER DATABASE OPEN resetlogs
*
ERROR at line 1:
ORA-01194: file 1 needs more recovery TO be consistent
ORA-01110: DATA file 1: '/home/oracle/travel/travel/system01.dbf'
SQL>
SQL> shutdown immediate
ORA-01109: DATABASE NOT OPEN
DATABASE dismounted.
ORACLE instance shut down.
SQL> startup nomount pfile='/home/oracle/travel/travel/b.ora
ORACLE instance started.
Total System Global Area? 626327552 bytes
Fixed Size????????????????? 2230952 bytes
Variable Size???????????? 184550744 bytes
Database Buffers????????? 436207616 bytes
Redo Buffers??????????????? 3338240 bytes
SQL> alter database mount
2? ;
Database altered.
SQL> alter session set events '10015 trace name ADJUST_SCN level 10';
Session altered.
SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-01589: must use RESETLOGS or NORESETLOGS option for database open
SQL> alter database open noresetlogs;
alter database open noresetlogs
*
ERROR at line 1:
ORA-01588: must use RESETLOGS option for database open
SQL> alter database open resetlogs;
Database altered.
SQL> show parameter name
NAME???????????????????????????????? TYPE??????? VALUE
-------------Oracleо----------------------- ----------- ------------------------------
db_file_name_convert???????????????? string
db_name????????????????????????????? string????? travel
db_unique_name?????????????????????? string????? travel
global_names???????????????????????? boolean???? FALSE
instance_name??????????????????????? string????? travel
lock_name_space????????????????????? string
log_file_name_convert??????????????? string
processor_group_name???????????????? string
service_names??????????????????????? string????? travel
SQL> select open_mode from v$database;
OPEN_MODE
--------------------
READ WRITE
SQL> alter system switch logfile;
System altered.
這里說(shuō)明一下是我的alert log里面還出現(xiàn)了數(shù)據(jù)字典不一致的問(wèn)題，因?yàn)楫吘故菑?qiáng)制open的，如下：
Sun Jan 20 00:25:34 2013
Errors in file /oracle/diag/diag/rdbms/travel/travel/trace/travel_m000_4681.trc:
ORA-25153: Temporary Tablespace is Empty
Sun Jan 20 00:25:38 2013
Errors in file /oracle/diag/diag/rdbms/travel/travel/trace/travel_j004_4692.trc? (incident=21817):
ORA-00600: internal error code, arguments: [kdsgrp1], [], [], [], [], [], [], [], [], [], [], []
Incident details in: /oracle/diag/diag/rdbms/travel/travel/incident/incdir_21817/travel_j004_4692_i21817.trc
Sun Jan 20 00:25:43 2013
Dumping diagnostic data in directory=[cdmp_20130120002543], requested by (instance=1, osid=4692 (J004)), summary=[incident=21817].
Use ADRCI or Support Workbench to package the incident.
See Note 411.1 at My Oracle Support for error and packaging details.
Sun Jan 20 00:25:47 2013
這個(gè)ora-600錯(cuò)誤很常見(jiàn)了，通過(guò)是index信息不一致。
其trace內(nèi)容如下：
* kdsgrp1-1: *************************************************
row 0x0040589e.4b continuation at
0x0040589e.4b file# 1 block# 22686 slot 75 not found
KDSTABN_GET: 0 ..... ntab: 1
curSlot: 75 ..... nrows: 75
kdsgrp - dump CR block dba=0x0040589e
Block header dump:? 0x0040589e
Object id on Block? Y
seg/obj: 0x12? csc: 0x00.3bca9? itc: 1? flg: O? typ: 1 - DATA
fsl: 0? fnx: 0x40589f ver: 0x01
Itl?????????? Xid????????????????? Uba???????? Flag? Lck??????? Scn/Fsc
0x01?? 0x0001.01a.000000a1? 0x00c05e97.001d.0d? --U-??? 1? fsc 0x0053.0003bcab
bdba: 0x0040589e
data_block_dump,data header at 0x7a26a044
===============
tsiz: 0x1fb8
hsiz: 0xa8
pbl: 0x7a26a044
76543210
flag=--------
ntab=1
nrow=75
frre=-1
fsbo=0xa8
...........
seg/obj: 0×12 這是obj$對(duì)象，屬于bootstrap$核心對(duì)象，涉及到這類的對(duì)象處理相對(duì)麻煩，針對(duì)這類情況，數(shù)據(jù)庫(kù)open后都建議把數(shù)據(jù)導(dǎo)出，然后重建庫(kù)，我這里就不在繼續(xù)描述這個(gè)ora-600錯(cuò)誤了，我博客也有類似的例子。
最后來(lái)個(gè)小節(jié)：
1. oracle通過(guò)系統(tǒng)checkpoint scn，datafile checkpoint scn,start scn三者之間的比較來(lái)判斷數(shù)據(jù)文件是否需要進(jìn)行介質(zhì)恢復(fù).
2. 在redo 線程打開(kāi)的情況下，即數(shù)據(jù)庫(kù)open的情況下，stop scn會(huì)被設(shè)置為無(wú)窮大，當(dāng)正常關(guān)閉時(shí)，stop scn等于datafile scn.
這里需要注意的是，stop scn是存放在controlfile中的，網(wǎng)上部分資料說(shuō)是存在datafile header中，這個(gè)說(shuō)法是錯(cuò)誤的。
3. oracle在open之前是先判斷是否進(jìn)行介質(zhì)恢復(fù)，然后再是判斷是否進(jìn)行instance recovery。
4. 關(guān)于4種scn的關(guān)系如下：
system checkpoint scn — 存放在controlfile中
datafile checkpoint scn –存放在controlfile中
start scn —存放在datafile header中
stop scn —存放在controlfile中
system scn，datafile checkpoint scn，start scn，這3種scn用于判斷數(shù)據(jù)文件是否需要進(jìn)行介質(zhì)恢復(fù)。這3個(gè)相等這不需要介質(zhì)恢復(fù)。
如何這4個(gè)都相等，那么就不需要進(jìn)行實(shí)例恢復(fù)。stop scn是用于判斷是否進(jìn)行實(shí)例恢復(fù)的。
5. 如果stop scn比其他的幾個(gè)scn要大，那么就需要進(jìn)行instance recover，需要進(jìn)行掃描redo，實(shí)例恢復(fù)的起點(diǎn)是low cache rba，終點(diǎn)
是redo log的最末端。
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最權(quán)威、專業(yè)的Oracle案例資源匯總之【案例】Oracle報(bào)錯(cuò)ORA-16433非歸檔丟失redo無(wú)法啟動(dòng)的恢復(fù)過(guò)程
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