[转]开启闪回以及闪回的四种原理

时间：2014-06-25 16:55:18 阅读：260 评论：0 收藏：0 [点我收藏+]

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1、首先确认db_recovery_file_dest和db_recovery_file_dest_size 有值。

sys@TEST0910> 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

sys@TEST0910> shutdown immediate

Database closed.

Database dismounted.

ORACLE instance shut down.

sys@TEST0910> 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.

sys@TEST0910> alter database flashback on;

Database altered.

sys@TEST0910> alter database open;

Database altered.

3、查询确认是否开启闪回

sys@TEST0910> 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

sys@TEST0910> select count(*) from scott.test10;

COUNT(*)

----------

2、误操作drop

sys@TEST0910> drop table scott.test10;

Table dropped.

3、登陆scoot用户，查询回收站

sys@TEST0910> conn scott/tiger

Connected.

scott@TEST0910> 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

scott@TEST0910> 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

scott@TEST0910> flashback table TEST10 to before drop [rename to test11];可以重命名

Flashback complete.

scott@TEST0910> select count(*) from test10;

COUNT(*)

----------

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 scott@TEST0910> select count(*) from test10;

COUNT(*)

----------

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 scott@TEST0910> delete from test10;

14 rows deleted.

11:52:31 scott@TEST0910> commit;

Commit complete.

11:52:35 scott@TEST0910> select count(*) from test10;

COUNT(*)

----------

3、使用闪回查询

11:54:25 scott@TEST0910> 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 scott@TEST0910> 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 scott@TEST0910> commit;

Commit complete.

11:55:30 scott@TEST0910> select count(*) from test10;

COUNT(*)

----------

flashback table实验（基于undo数据）

1、查询原数据

sys@TEST0910> select count(*) from test10;

COUNT(*)

----------

1 row selected.

2、查询数据库当前scn号，稍后作为恢复参考

sys@TEST0910> select checkpoint_change# from v$database;

CHECKPOINT_CHANGE#

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

1952615

1 row selected.

3、误操作

sys@TEST0910> delete from scott.test10;

14 rows deleted.

sys@TEST0910> commit;

Commit complete.

4、根据之前的scn号使用undo数据闪回查询

sys@TEST0910> 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。

sys@TEST0910> 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

sys@TEST0910> alter table scott.test10 enable row movement;

Table altered.

sys@TEST0910> flashback table scott.test10 to scn 1952615;

Flashback complete.

sys@TEST0910> select count(*) from scott.test10;

COUNT(*)

----------

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

sys@TEST0910> 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

sys@TEST0910> 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

ys@TEST0910> select name,flashback_on from v$database;

NAME FLASHBACK_ON

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

TEST0910 YES

1 row selected.

2、查询原数据

sys@TEST0910> select count(*) from scott.test12;

COUNT(*)

----------

1 row selected.

3.激活logmnr，注意，必须有此步骤，不然logmnr出不来数据

sys@TEST0910> ALTER DATABASE ADD SUPPLEMENTAL LOG DATA;

Database altered.

4、误操作DDL操作

sys@TEST0910> truncate table scott.test12;

Table truncated.

sys@TEST0910> select count(*) from scott.test12;

COUNT(*)

----------

1 row selected.

5、查询当前日志组和归档日志

sys@TEST0910> 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.

sys@TEST0910> 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.

sys@TEST0910> 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

sys@TEST0910> 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.

sys@TEST0910> EXECUTE DBMS_LOGMNR.ADD_LOGFILE( -

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

> OPTIONS => DBMS_LOGMNR.NEW);

PL/SQL procedure successfully completed.

sys@TEST0910> 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.

sys@TEST0910> 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.

sys@TEST0910> 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.

sys@TEST0910> 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

sys@TEST0910> alter session set nls_date_format=‘yyyy-mm-dd hh24:mi:ss‘;

Session altered.

8、查询logmnr分析出的数据

sys@TEST0910> 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;

sys@TEST0910> EXECUTE DBMS_LOGMNR.END_LOGMNR;

PL/SQL procedure successfully completed.

8、mount状态下闪回

sys@TEST0910> shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

sys@TEST0910> 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.

sys@TEST0910> 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

sys@TEST0910> alter database open read only;

Database altered.

sys@TEST0910> select count(*) from scott.test12;

COUNT(*)

----------

1 row selected.

10、重新启动数据库，使用resetlogs打开数据库

sys@TEST0910> shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

sys@TEST0910> 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.

sys@TEST0910> alter database open

2 ;

alter database open

ERROR at line 1:

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

sys@TEST0910> alter database open resetlogs;

Database altered.

[转]开启闪回以及闪回的四种原理,布布扣,bubuko.com

[转]开启闪回以及闪回的四种原理

标签：des blog http tar ext com

原文地址：http://www.cnblogs.com/gispf/p/3806221.html

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