[转]开启闪回以及闪回的四种原理

1、首先确认db_recovery_file_dest和db_recovery_file_dest_size 有值。

[email protected]> show parameter recovery

NAME                                 TYPE        VALUE

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

db_recovery_file_dest                string      /u01/app/oracle/fast_recovery_ area

db_recovery_file_dest_size           big integer 4122M

db_recovery_file_dest 放闪回日志，默认路径/u01/app/oracle/fast_recovery_ area

db_recovery_file_dest_size 存放闪回日志空间的大小，默认4122M

2、开启闪回

[email protected]> shutdown immediate

Database closed.

Database dismounted.

ORACLE instance shut down.

[email protected]> startup mount

ORACLE instance started.

Total System Global Area 2505338880 bytes

Fixed Size                  2230952 bytes

Variable Size             587203928 bytes

Database Buffers         1895825408 bytes

Redo Buffers               20078592 bytes

Database mounted.

[email protected]> alter database flashback on;

Database altered.

[email protected]> alter database open;

Database altered.

3、查询确认是否开启闪回

[email protected]> select name,flashback_on from v$database;

NAME                                               FLASHBACK_ON

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

TEST0910                                           YES

闪回四种不同原理

  • flashback drop：利用recyelebin 回收站原理
  • flashback table TEST10 to before drop [rename to test11];可以重命名
  • flashback query ，依赖undo数据，先查询，在做insert
  • insert into test10 select * from test10 as of timestamp to_timestamp(‘2013-09-23 11:52:06‘,‘yyyy-mm-dd hh24:mi:ss‘);
  • flashback table 依赖undo块
  • flashback table scott.test10 to scn 1952615
  • insert into test10 select * from scott.test10 as of scn 1952615;
  • flashback database DDL语句，依赖闪回区的闪回日志
  • flashback database to timestamp to_timestamp(‘2013-09-23 15:09:52‘,‘yyyy-mm-dd hh24:mi:ss‘);时间减一秒。
  • 闪回归档--create as

来源：http://blog.csdn.net/rlhua/article/details/11934831

flashback drop实验（sys用户的除外，它没有回收站）

1、查询原来表的数量

[email protected]> select count(*) from scott.test10;

COUNT(*)

----------

14

2、误操作drop

[email protected]> drop table scott.test10;

Table dropped.

3、登陆scoot用户，查询回收站

[email protected]> conn scott/tiger

Connected.

[email protected]> show recyclebin

ORIGINAL NAME    RECYCLEBIN NAME                OBJECT TYPE  DROP TIME

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

TEST10           BIN$5w/YlwePKa7gQwEAAH+tZw==$0 TABLE        2013-09-23:11:40:56

4、查询回收站里的内容

[email protected]>  select * from "BIN$5w/YlwePKa7gQwEAAH+tZw==$0";              ------注意：此处是双引号

EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO

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

7369 SMITH      CLERK           7902 17-DEC-80        800                    20

7499 ALLEN      SALESMAN        7698 20-FEB-81       1600        300         30

7521 WARD       SALESMAN        7698 22-FEB-81       1250        500         30

7566 JONES      MANAGER         7839 02-APR-81       2975                    20

7654 MARTIN     SALESMAN        7698 28-SEP-81       1250       1400         30

7698 BLAKE      MANAGER         7839 01-MAY-81       2850                    30

7782 CLARK      MANAGER         7839 09-JUN-81       2450                    10

7788 SCOTT      ANALYST         7566 19-APR-87       3000                    20

7839 KING       PRESIDENT            17-NOV-81       5000                    10

7844 TURNER     SALESMAN        7698 08-SEP-81       1500          0         30

7876 ADAMS      CLERK           7788 23-MAY-87       1100                    20

7900 JAMES      CLERK           7698 03-DEC-81        950                    30

7902 FORD       ANALYST         7566 03-DEC-81       3000                    20

7934 MILLER     CLERK           7782 23-JAN-82       1300                    10

14 rows selected.

5、两种闪回方式

使用insert into TEST10 select * from "BIN$5w/YlwePKa7gQwEAAH+tZw==$0";  闪回

使用flashback table闪回

[email protected]> flashback table TEST10 to before drop [rename to test11];可以重命名

Flashback complete.

[email protected]> select count(*) from test10;

COUNT(*)

----------

14

flashback query实验（基于undo数据）

误操作DML语句，刚刚发生，undo没有被覆盖

1、查询原数据

11:52:06 [email protected]> select count(*) from test10;

COUNT(*)

----------

14

11:52:06 这个时间点还有数据，稍后作为参考

2、误操作

11:52:19 [email protected]> delete from test10;

14 rows deleted.

11:52:31 [email protected]> commit;

Commit complete.

11:52:35 [email protected]> select count(*) from test10;

COUNT(*)

----------

0

3、使用闪回查询

11:54:25 [email protected]> select * from test10 as of timestamp to_timestamp(‘2013-09-23 11:52:06‘,‘yyyy-mm-dd hh24:mi:ss‘);

EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO

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

7369 SMITH      CLERK           7902 17-DEC-80        800                    20

7499 ALLEN      SALESMAN        7698 20-FEB-81       1600        300         30

7521 WARD       SALESMAN        7698 22-FEB-81       1250        500         30

7566 JONES      MANAGER         7839 02-APR-81       2975                    20

7654 MARTIN     SALESMAN        7698 28-SEP-81       1250       1400         30

7698 BLAKE      MANAGER         7839 01-MAY-81       2850                    30

7782 CLARK      MANAGER         7839 09-JUN-81       2450                    10

7788 SCOTT      ANALYST         7566 19-APR-87       3000                    20

7839 KING       PRESIDENT            17-NOV-81       5000                    10

7844 TURNER     SALESMAN        7698 08-SEP-81       1500          0         30

7876 ADAMS      CLERK           7788 23-MAY-87       1100                    20

7900 JAMES      CLERK           7698 03-DEC-81        950                    30

7902 FORD       ANALYST         7566 03-DEC-81       3000                    20

7934 MILLER     CLERK           7782 23-JAN-82       1300                    10

14 rows selected.

4、插入闪回查询的结果

11:54:44 [email protected]> insert into test10 select * from test10 as of timestamp to_timestamp(‘2013-09-23 11:52:06‘,‘yyyy-mm-dd hh24:mi:ss‘);

14 rows created.

11:55:02 [email protected]> commit;

Commit complete.

11:55:30 [email protected]> select count(*) from test10;

COUNT(*)

----------

14

flashback table实验（基于undo数据）

1、查询原数据

[email protected]> select count(*) from test10;

COUNT(*)

----------

14

1 row selected.

2、查询数据库当前scn号，稍后作为恢复参考

[email protected]> select checkpoint_change# from v$database;

CHECKPOINT_CHANGE#

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

1952615

1 row selected.

3、误操作

[email protected]> delete from scott.test10;

14 rows deleted.

[email protected]> commit;

Commit complete.

4、根据之前的scn号使用undo数据闪回查询

[email protected]> select * from scott.test10 as of scn 1952615;

EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO

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

7369 SMITH      CLERK           7902 17-DEC-80        800                    20

7499 ALLEN      SALESMAN        7698 20-FEB-81       1600        300         30

7521 WARD       SALESMAN        7698 22-FEB-81       1250        500         30

7566 JONES      MANAGER         7839 02-APR-81       2975                    20

7654 MARTIN     SALESMAN        7698 28-SEP-81       1250       1400         30

7698 BLAKE      MANAGER         7839 01-MAY-81       2850                    30

7782 CLARK      MANAGER         7839 09-JUN-81       2450                    10

7788 SCOTT      ANALYST         7566 19-APR-87       3000                    20

7839 KING       PRESIDENT            17-NOV-81       5000                    10

7844 TURNER     SALESMAN        7698 08-SEP-81       1500          0         30

7876 ADAMS      CLERK           7788 23-MAY-87       1100                    20

7900 JAMES      CLERK           7698 03-DEC-81        950                    30

7902 FORD       ANALYST         7566 03-DEC-81       3000                    20

7934 MILLER     CLERK           7782 23-JAN-82       1300                    10

14 rows selected.

5、将数据还原

可以插入回去，如闪回查询那样：insert into test10 select * from scott.test10 as of scn 1952615;

另外一种，可以用闪回表的方式：flashback table scott.test10 to scn 1952615;

注意，闪回表时要开启 row movement，不然要报错。

[email protected]> flashback table scott.test10 to scn 1952615;

flashback table scott.test10 to scn 1952615

*

ERROR at line 1:

ORA-08189: cannot flashback the table because row movement is not enabled

[email protected]> alter table scott.test10 enable row movement;

Table altered.

[email protected]> flashback table scott.test10 to scn 1952615;

Flashback complete.

[email protected]> select count(*) from scott.test10;

COUNT(*)

----------

14

1 row selected.

flashback database实验（使用lgmnr找出还原时间点）

过程：激活日志--删数据--查日志--logmnr--关库--不用转储--mount--flashback数据库（时间减一秒）--read only

开库看正确与否--关库--mount--开库resetlogs

DDL语句的恢复：类似不完全恢复，可以恢复到某个时间点，依赖flashback log.

logmnr依赖的是redo和归档。

flashback database一般用于ddl操作，

dml用flashback query或flashback table。因为他们读undo块

ddl语句不生成undo块

闪回数据库有限制：比如解决不了media recovery等（硬盘坏了等）。还是备份最重要。

1、使用logmnr来记录时间点，首先必须设置有一下参数

show parameter utl; logmnr需要的路径

[email protected]> show parameter utl

NAME                                 TYPE        VALUE

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

create_stored_outlines               string

utl_file_dir                         string      /u01/app/oracle/utl

使用flashback database首先设置两个参数：

db_recovery_file_dest                string      /u01/app/oracle/fast_recovery_area

db_recovery_file_dest_size           big integer 4122M

[email protected]0> show parameter recovery

NAME                                 TYPE        VALUE

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

db_recovery_file_dest                string      /u01/app/oracle/fast_recovery_

area

db_recovery_file_dest_size           big integer 4122M

而且需要alter database flashback on

[email protected]> select name,flashback_on from v$database;

NAME                                               FLASHBACK_ON

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

TEST0910                                           YES

1 row selected.

2、查询原数据

[email protected]> select count(*) from scott.test12;

COUNT(*)

----------

14

1 row selected.

3.激活logmnr，注意，必须有此步骤，不然logmnr出不来数据

[email protected]> ALTER DATABASE ADD SUPPLEMENTAL LOG DATA;

Database altered.

4、误操作DDL操作

[email protected]> truncate table scott.test12;

Table truncated.

[email protected]> select count(*) from scott.test12;

COUNT(*)

----------

0

1 row selected.

5、查询当前日志组和归档日志

[email protected]> select * from v$log;

GROUP#    THREAD#  SEQUENCE#      BYTES  BLOCKSIZE    MEMBERS ARC STATUS           FIRST_CHANGE# FIRST_TIME          NEXT_CHANGE# NEXT_TIME

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

1          1          7   52428800        512          1 YES INACTIVE               1977009 2013-09-23 15:04:56      1981677 2013-09-23 15:05:11

2          1          8   52428800        512          1 YES ACTIVE                 1981677 2013-09-23 15:05:11      1985831 2013-09-23 15:05:41

3          1          9   52428800        512          1 NO  CURRENT                1985831 2013-09-23 15:05:41   2.8147E+14

3 rows selected.

[email protected]> select * from v$logfile;

GROUP# STATUS  TYPE    MEMBER                                             IS_

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

2         ONLINE  /u01/app/oracle/oradata/test0910/redo02.log        NO

1         ONLINE  /u01/app/oracle/oradata/test0910/redo01.log        NO

3         ONLINE  /u01/app/oracle/oradata/test0910/redo03.log        NO

3 rows selected.

[email protected]> select name from v$archived_log;

NAME

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

/u01/app/oracle/fast_recovery_area/TEST0910/archivelog/2013_09_23/o1_mf_1_6_94146rg7_.arc

/u01/app/oracle/fast_recovery_area/TEST0910/archivelog/2013_09_23/o1_mf_1_7_941477xf_.arc

/u01/app/oracle/fast_recovery_area/TEST0910/archivelog/2013_09_23/o1_mf_1_8_941485th_.arc

61 rows selected.

6、执行logmnr

EXECUTE DBMS_LOGMNR_D.BUILD(‘dictionary.ora‘, -

‘/u01/app/oracle/utl‘, -

DBMS_LOGMNR_D.STORE_IN_FLAT_FILE);

EXECUTE DBMS_LOGMNR.ADD_LOGFILE( -

LOGFILENAME => ‘/u01/app/oracle/oradata/test0910/redo03.log‘, -

OPTIONS => DBMS_LOGMNR.NEW);

EXECUTE DBMS_LOGMNR.ADD_LOGFILE( -

LOGFILENAME => ‘/u01/app/oracle/fast_recovery_area/TEST0910/archivelog/2013_09_23/o1_mf_1_6_94146rg7_.arc‘, -

OPTIONS => DBMS_LOGMNR.ADDFILE);

EXECUTE DBMS_LOGMNR.ADD_LOGFILE( -

LOGFILENAME => ‘/u01/app/oracle/fast_recovery_area/TEST0910/archivelog/2013_09_23/o1_mf_1_7_941477xf_.arc‘, -

OPTIONS => DBMS_LOGMNR.ADDFILE);

EXECUTE DBMS_LOGMNR.ADD_LOGFILE( -

LOGFILENAME => ‘/u01/app/oracle/fast_recovery_area/TEST0910/archivelog/2013_09_23/o1_mf_1_8_941485th_.arc‘, -

OPTIONS => DBMS_LOGMNR.ADDFILE);

EXECUTE DBMS_LOGMNR.START_LOGMNR( -

DICTFILENAME =>‘/u01/app/oracle/utl/dictionary.ora‘,OPTIONS => -

DBMS_LOGMNR.DDL_DICT_TRACKING);

EXECUTE DBMS_LOGMNR.END_LOGMNR;

logminer官方参考：http://docs.oracle.com/cd/E11882_01/server.112/e22490/logminer.htm#i1009063

以下为执行步骤

[email protected]> EXECUTE DBMS_LOGMNR_D.BUILD(‘dictionary.ora‘, -

> ‘/u01/app/oracle/utl‘, -

> DBMS_LOGMNR_D.STORE_IN_FLAT_FILE);

LogMnr Dictionary Procedure started

LogMnr Dictionary File Opened

Procedure executed successfully - LogMnr Dictionary Created

PL/SQL procedure successfully completed.

[email protected]> EXECUTE DBMS_LOGMNR.ADD_LOGFILE( -

> LOGFILENAME => ‘/u01/app/oracle/oradata/test0910/redo03.log‘, -

> OPTIONS => DBMS_LOGMNR.NEW);

PL/SQL procedure successfully completed.

[email protected]> EXECUTE DBMS_LOGMNR.ADD_LOGFILE( -

> LOGFILENAME => ‘/u01/app/oracle/fast_recovery_area/TEST0910/archivelog/2013_09_23/o1_mf_1_8_941485th_.arc‘, -

> OPTIONS => DBMS_LOGMNR.ADDFILE);

PL/SQL procedure successfully completed.

[email protected]>  EXECUTE DBMS_LOGMNR.ADD_LOGFILE( -

> LOGFILENAME => ‘/u01/app/oracle/fast_recovery_area/TEST0910/archivelog/2013_09_23/o1_mf_1_7_941477xf_.arc‘, -

> OPTIONS => DBMS_LOGMNR.ADDFILE);

PL/SQL procedure successfully completed.

[email protected]> EXECUTE DBMS_LOGMNR.ADD_LOGFILE( -

> LOGFILENAME => ‘/u01/app/oracle/fast_recovery_area/TEST0910/archivelog/2013_09_23/o1_mf_1_6_94146rg7_.arc‘, -

> OPTIONS => DBMS_LOGMNR.ADDFILE);

PL/SQL procedure successfully completed.

[email protected]> EXECUTE DBMS_LOGMNR.START_LOGMNR( -

> DICTFILENAME =>‘/u01/app/oracle/utl/dictionary.ora‘,OPTIONS => -

> DBMS_LOGMNR.DDL_DICT_TRACKING);

PL/SQL procedure successfully completed.

7、设置session时间格式

[email protected]> alter session set nls_date_format=‘yyyy-mm-dd hh24:mi:ss‘;

Session altered.

8、查询logmnr分析出的数据

[email protected]> select username,scn,timestamp,sql_redo from v$logmnr_contents

2  where seg_name=‘TEST12‘;

USERNAME                              SCN TIMESTAMP           SQL_REDO

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

SYS                               1989009 2013-09-23 15:09:53 truncate table scott.test12;

[email protected]> EXECUTE DBMS_LOGMNR.END_LOGMNR;

PL/SQL procedure successfully completed.

8、mount状态下闪回

[email protected]> shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

[email protected]> startup mount;

ORACLE instance started.

Total System Global Area 2505338880 bytes

Fixed Size                  2230952 bytes

Variable Size             587203928 bytes

Database Buffers         1895825408 bytes

Redo Buffers               20078592 bytes

Database mounted.

[email protected]> flashback database to timestamp to_timestamp(‘2013-09-23 15:09:52‘,‘yyyy-mm-dd hh24:mi:ss‘);

此处注意，时间在logmnr查询出的基础上减1秒

Flashback complete.

9、让数据库置于read only，检查数据是否正确恢复

[email protected]> alter database open read only;

Database altered.

[email protected]> select count(*) from scott.test12;

COUNT(*)

----------

14

1 row selected.

10、重新启动数据库，使用resetlogs打开数据库

[email protected]> shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

[email protected]> startup mount;

ORACLE instance started.

Total System Global Area 2505338880 bytes

Fixed Size                  2230952 bytes

Variable Size             587203928 bytes

Database Buffers         1895825408 bytes

Redo Buffers               20078592 bytes

Database mounted.

[email protected]> alter database open

2  ;

alter database open

*

ERROR at line 1:

ORA-01589: must use RESETLOGS or NORESETLOGS option for database open

[email protected]> alter database open resetlogs;

Database altered.

[转]开启闪回以及闪回的四种原理

时间： 2024-08-01 09:20:12

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