介紹

Oracle Redo 損壞分三種情況:unused 狀態日誌損壞 inactive 狀態日誌損壞 active 狀態日誌損壞 current 狀態日誌損壞

恢復

與inactive 狀態日誌損壞

如果這個日誌是inactive, 手動執行clearing 操作:

SQL> alter database clear logfile group 2;

alter database clear logfile group 2

*

第 1 行出現錯誤:

ORA-00350: 日誌 2 ( 例項 orcl 的日誌, 執行緒 1) 需要歸檔

ORA-00312: 聯機日誌 2 執行緒 1:

F:ORACLEPRODUCT10.2.0ORADATAORCLREDO02.LOG

執行如下操作:

SQL> alter database clear unarchived logfile group 2;

資料庫已更改。

狀態日誌損壞

存在歸檔直接使用歸檔恢復即可.

SYS@orcl11g>recover database until cancel; -- 指定恢復的時間點( 如果不知道，就是untill cancel)

ORA-00279: change 1763218 generated at 06/24/2021 12:02:00 needed for thread 1

ORA-00289: suggestion : /u01/app/oracle/arch/1_74_816622368.dbf

ORA-00280: change 1763218 for thread 1 is in sequence #74

Specify log: {<RET>=suggested | filename | AUTO | CANCEL}

/u01/app/oracle/arch/1_74_816622368.dbf

ORA-00279: change 1769094 generated at 06/24/2021 13:34:43 needed for thread 1

ORA-00289: suggestion : /u01/app/oracle/arch/1_75_816622368.dbf

ORA-00280: change 1769094 for thread 1 is in sequence #75

ORA-00278: log file '/u01/app/oracle/arch/1_74_816622368.dbf' no longer needed for this recovery

Specify log: {<RET>=suggested | filename | AUTO | CANCEL}

/u01/app/oracle/oradata/orcl11g/redo01.log -- 指定current 日誌

Log applied.

Media recovery complete.

狀態日誌損壞

常規情況:

設定隱藏引數:

SYS@orcl11g> recover database until cancel;

ORA-00279: change 1789650 generated at 06/24/2021 13:40:21 needed for thread 1

ORA-00289: suggestion : /u01/app/oracle/arch/1_2_818948248.dbf

ORA-00280: change 1789650 for thread 1 is in sequence #2

Specify log: {<RET>=suggested | filename | AUTO | CANCEL}

/u01/app/oracle/arch/1_2_818948248.dbf

ORA-00279: change 1789904 generated at 06/24/2021 13:41:02 needed for thread 1

ORA-00289: suggestion : /u01/app/oracle/arch/1_3_818948248.dbf

ORA-00280: change 1789904 for thread 1 is in sequence #3

ORA-00278: log file '/u01/app/oracle/arch/1_2_818948248.dbf' no longer needed

for this recovery

Specify log: {<RET>=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: '/u01/app/oracle/oradata/orcl11g/system01.dbf'

SYS@orcl11g> alter database open resetlogs;

Database altered.

如若出現與 SCN 相關 ORA-00600 錯誤使用以下推進 SCN 方式進行處理

推進scn 修復

1. 檢視當前資料庫的Current SCN

SYS@orcl> select current_scn||'' from v$database;

CURRENT_SCN||''

--------------------------------------------------------------------------------

4563483988

可以看到當前SCN 是4563 483988 ，我現在想推進SCN ，在10w 級別，也就是4563483988 標紅數字修改為指定值。

2. 重新啟動資料庫到mount 階段

SYS@orcl> shutdown abort

ORACLE instance shut down.

SYS@orcl> startup mount

ORACLE instance started.

Total System Global Area 1235959808 bytes

Fixed Size 2252784 bytes

Variable Size 788529168 bytes

Database Buffers 436207616 bytes

Redo Buffers 8970240 bytes

Database mounted.

3. 使用oradebug poke 推進SCN

我這裡直接把十萬位的"4" 改為"9" 了，相當於推進了50w 左右：說明：實驗發現oradebug poke 推進的SCN 值，既可以指定十六進位制的0x11008DE74 ，也可以直接指定十進位制的4563983988 。

SYS@orcl> oradebug setmypid

Statement processed.

SYS@orcl> oradebug dumpvar sga kcsgscn_

kcslf kcsgscn_ [06001AE70, 06001AEA0) = 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 6001AB50 00000000

SYS@orcl> select to_char(checkpoint_change#, 'XXXXXXXXXXXXXXXX') from v$database;

TO_CHAR(CHECKPOINT_CHANGE#,'XXXXXX

----------------------------------

110013C41

SYS@orcl> oradebug poke 0x06001AE70 8 4563983988

BEFORE: [06001AE70, 06001AE78) = 00000000 00000000

AFTER: [06001AE70, 06001AE78) = 1008DE74 00000001

SYS@orcl> oradebug dumpvar sga kcsgscn_

kcslf kcsgscn_ [06001AE70, 06001AEA0) = 1008DE74 00000001 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 6001AB50 00000000

SYS@orcl> alter database open;

Database altered.

SYS@orcl> select current_scn||'' from v$database;

CURRENT_SCN||''

--------------------------------------------------------------------------------

4563984271

可以看到已經成功將SCN 推進到4563983988 ，SCN 不斷增長，所以這裡查到的值略大一些。

4. 舉例ORA-600[2662] 錯誤下poke 計算方式

A data block SCN is ahead of the current SCN.

The ORA-600 [2662] occurs when an SCN is compared to the dependent SCN stored in a UGA variable.

If the SCN is less than the dependent SCN then we signal the ORA-600 [2662] internal error.

ARGUMENTS:

Arg [a] Current SCN WRAP

Arg [b] Current SCN BASE

Arg [c] dependent SCN WRAP

Arg [d] dependent SCN BASE

Arg [e] Where present this is the DBA where the dependent SCN came from.

計算方式:

ORA-00600: internal error code, arguments: [2662], [2], [1424107441], [2], [1424142235], [8388617], [], []

select 2*power(2,32)+1424142235 from dual;

10014076827

ORA-00600: internal error code, arguments: [2662], [2], [1424142249], [2], [1424142302], [8388649], [], []

select 2*power(2,32)+1424143000 from dual;

10014077592

總結公式：c * power(2,32) + d {+ 可適當加一點，但不要太大！}

c 代表：Arg [c] dependent SCN WRAP

d 代表：Arg [d] dependent SCN BASE

推進scn 修復

計算方式

Lowest_scn+event level * 1000000

檢視當前資料庫SCN:

SQL> select to_char(current_scn) from v$database;

TO_CHAR(CURRENT_SCN)

----------------------------------------

12796139551520

2. 新增event 以及引數

alter system set "_allow_resetlogs_corruption"=true scope=spfile;

alter system set event='21307096 trace name context forever,level 3' scope=spfile;

3. 啟動資料庫

SQL> shutdown immediate;

Database dismounted.

ORACLE instance shut down.

SQL> startup mount;

ORACLE instance started.

Total System Global Area 1660944384 bytes

Fixed Size 8793448 bytes

Variable Size 889193112 bytes

Database Buffers 754974720 bytes

Redo Buffers 7983104 bytes

Database mounted.

SQL> recover database using backup controlfile until cancel;

ORA-00279: change 12796139551734 generated at 04/20/2022 11:13:44 needed for

thread 1

ORA-00289: suggestion :

/app/oracle/product/12.2.0/db_1/dbs/arch1_1_1102504135.dbf

ORA-00280: change 12796139551734 for thread 1 is in sequence #1

Specify log: {<RET>=suggested | filename | AUTO | CANCEL}

cancel

Media recovery cancelled.

SQL>

SQL> alter database open resetlogs;

Database altered.

SQL> select to_char(current_scn) from v$database;

TO_CHAR(CURRENT_SCN)

----------------------------------------

12796142552279

SCN 成功推進300w

推進scn 修復

Session 1:

查詢當前scn:
SQL> select current_scn from v$database;

CURRENT_SCN

-----------

2910718245

查詢當前SCN 轉成16 進位制後的值：

SQL> select to_char(2910718245,'xxxxxxxxxxxx') from dual;

TO_CHAR(29107

-------------

ad7e0925

查詢預修改的 SCN 轉換成 16 進位制後的值，本次將最高位增加一位數

SQL> select to_char(3910718245,'xxxxxxxxxxxx') from dual;

TO_CHAR(39107

-------------

e918d325

SQL> oradebug setmypid

Statement processed.

SQL> oradebug dumpvar sga kcsgscn_

kscn8 kcsgscn_ [060017E98, 060017EA0) = AD7E093B 00000000

需要注意的是，060017E98 是SCN BASE 值，AD7E093B 是當前的SCN 值，可以理解為060017E98 是一個代號x ，當前的x 等於AD7E093B ，待會兒我們修改SCN 值的時候，就會需要指定060017E98 這個值等於多少。

Session 2:

[oracle@redhat19c11 ~]$ ps -ef|grep LOCAL=YES

oracle 9824 9730 0 Feb22 ? 00:00:01 oracleorcl (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))

oracle 18621 8636 0 01:18 pts/1 00:00:00 grep --color=auto LOCAL=YES

oracle 20109 20105 0 Feb15 ? 00:00:13 oracletestdb19c (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))

本次測試庫是orcl ，因此選9824

[oracle@redhat19c11 ~]$ gdb $ORACLE_HOME/bin/oracle 9824

GNU gdb (GDB) Red Hat Enterprise Linux 7.6.1-114.el7

License GPLv3+: GNU GPL version 3 or later <

This is free software: you are free to change and redistribute it.

There is NO WARRANTY, to the extent permitted by law. Type "show copying"

and "show warranty" for details.

This GDB was configured as "x86_64-redhat-linux-gnu".

For bug reporting instructions, please see:

-------------------------------------------

(gdb) set *((int *) 0x060017E98) = 0xe918d32---> 將SCN BASE 修改為剛才查出來的值

(gdb) quit

A debugging session is active.

Inferior 1 [process 9824] will be detached.

Quit anyway? (y or n) y

Detaching from program: /oracle/app/product/19.3.0/db_1/bin/oracle, process 9824

返回session1 查詢, 修改成功:

SQL> select current_scn from v$database;

CURRENT_SCN

-----------

3910718287

重啟資料庫, 也可正常開啟資料庫

SQL> shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

SQL> startup;

ORACLE instance started.

Total System Global Area 2466250400 bytes

Fixed Size 9137824 bytes

Variable Size 603979776 bytes

Database Buffers 1845493760 bytes

Redo Buffers 7639040 bytes

Database mounted.

Database opened.

SQL> select current_scn from v$database;

CURRENT_SCN

-----------

3910719415

Oracle Redo丟失恢復方案

介紹

恢復

與inactive 狀態日誌損壞

狀態日誌損壞

狀態日誌損壞

推進scn 修復

推進scn 修復

推進scn 修復

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