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模拟rac环境数据恢复

rac节点：192.168.100.201、192.168.100.202

确认：flashback已经开启

SQL> select name,current_scn,flashback_on from v$database;

查看flashb相关配置

SQL> col name format a32 heading 'parameter'

SQL> col value format a32 heading 'setting'

SQL> select name,value from v$parameter where name like '%flash%' or name like '%recovery%' order by name;

parameter setting

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

db_flashback_retention_target 1440

db_recovery_file_dest +RECOVERY

db_recovery_file_dest_size 19327352832

recovery_parallelism 0

确认flashback相关配置

创建测试数据和表

[oracle@rac2 ~]$ sqlplus jscn/jscn

SQL*Plus: Release 10.2.0.4.0 - Production on Sat Dec 3 15:11:17 2011

Copyright (c) 1982, 2007, Oracle. All Rights Reserved.

Connected to:

Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bit Production

With the Partitioning, Real Application Clusters, OLAP, Data Mining

and Real Application Testing options

SQL> create table test as (select TABLE_NAME,TABLESPACE_NAME from user_tables);

SQL> select * from test;

TABLE_NAME TABLESPACE_NAME

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

SALE_CITY JSCNDATA

SATISFACTION JSCNDATA

SENSITIVE_CHAR JSCNDATA

SHIPPAY_RELATION JSCNDATA

SHIPTYPE JSCNDATA

SHOP_APP_RES JSCNDATA

SHOP_MANAGER_DATA JSCNDATA

SHOP_MANAGER_R_REL JSCNDATA

SHOP_RIGHT JSCNDATA

SHOP_ROLE JSCNDATA

SHOP_ROLE_DATA JSCNDATA

TABLE_NAME TABLESPACE_NAME

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

SHOP_ROLE_R_REL JSCNDATA

SQL> purge recyclebin;

下面模式的是在rac环境下数据恢复的情况

1、flashback drop(闪回删除)

SQL> drop table test;

查看回收站：两个所有节点都能看到

SQL> select OBJECT_NAME,ORIGINAL_NAME from recyclebin;

OBJECT_NAME ORIGINAL_NAME

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

BIN$syvRE6lEabHgQAB/AQBDjA==$0 TEST

闪回表（任何节点都能可以执行）

SQL> flashback table test to before drop;

Flashback complete.

验证

SQL> desc test;

Name Null? Type

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

TABLE_NAME NOT NULL VARCHAR2(30)

TABLESPACE_NAME VARCHAR2(30)

SQL> select * from test;

TABLE_NAME TABLESPACE_NAME

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

SALE_CITY JSCNDATA

SATISFACTION JSCNDATA

SENSITIVE_CHAR JSCNDATA

SHIPPAY_RELATION JSCNDATA

SHIPTYPE JSCNDATA

2. flashback table(闪回表)

有时，不小心，对表进行了错误的update，那么我们就可以通过这个feature来进行恢复，

flashback table testtable to timestamp to_date（(’2009-05-13 00:35:50′, ‘yyyy-mm-dd hh24:mi:ss’)）

这里是利用undo表做恢复的基准，所以有关undo的参数undo_management和undo_retention对这个有影响。具体可以看看这两个参数的说明文档。

注，flashback table是只能处理DML操作过后的语句的恢复，如果在期间有DDL语句操作到这个表上，做flashback table时将

报错ORA-01466: unable to read data - table definition has changed。在做flashback table时先要alter table t enable row movement。

以下为示例：

[oracle@rac2 ~]$ sqlplus jscn/jscn

SQL> create table test_del as ( select TABLE_NAME,TABLESPACE_NAME from user_tables where rownum<=127);

SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;

to_char(sysdate,'yyyy-mm-dd hh24:mi:ss')

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

2011-12-03 16:36:43

SQL> delete from test_del;

127 rows deleted.

SQL> commit;

Commit complete.

SQL> select count(*) from test_del;

COUNT(*)

----------

0

SQL> select count(*) from test_del as of timestamp to_timestamp('2011-12-03 16:36:43','yyyy-mm-dd hh24:mi:ss');

COUNT(*)

----------

127

使用flashback table技术恢复数据

SQL> insert into test_del select * from test_del as of timestamp to_timestamp('2011-12-03 16:36:43','yyyy-mm-dd hh24:mi:ss');

127 rows created.

SQL> select count(*) from test_del;

COUNT(*)

----------

127

看到了吗，数据回来了

3、flashback database(闪回数据库)

对应flashback database来说，一般用来处理误删除了user或者一些错误的数据操作。

要使用flash database的特性。我们一定要启动flashback功能，

SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;

to_char(sysdate,'yyyy-mm-dd hh24:mi:ss')

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

2011-12-03 15:34:27

SQL> drop table test;

Table dropped.

SQL> purge recyclebin;

Recyclebin purged.

SQL> flashback table test to before drop;

flashback table test to before drop

*

ERROR at line 1:

ORA-38305: object not in RECYCLE BIN

这个时候flashback drop就不能用了，那么我们要用flashback database

首先，查询flashback database所能退回到最早时间

SQL> desc v$flashback_database_log;

Name Null? Type

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

OLDEST_FLASHBACK_SCN NUMBER

OLDEST_FLASHBACK_TIME DATE

RETENTION_TARGET NUMBER

FLASHBACK_SIZE NUMBER

ESTIMATED_FLASHBACK_SIZE NUMBER

col OLDEST_FLASHBACK_SCN for 999999999 heading 'oldest|flashback|scn#'

col OLDEST_FLASHBACK_TIME for a20 heading 'oldest|flashback|time#'

col RETENTION_TARGET for 999999999 heading 'RETENTION|TARGET'

col FLASHBACK_SIZE for 999999999 heading 'FLASHBACKt|SIZE'

col ESTIMATED_FLASHBACK_SIZE for 999999999 heading 'ESTIMATED|FLASHBACK_SIZE '

select OLDEST_FLASHBACK_SCN,to_char(OLDEST_FLASHBACK_TIME,'yyyy-mm-dd hh24:mi:ss') OLDEST_FLASHBACK_TIME,

RETENTION_TARGET,FLASHBACK_SIZE,ESTIMATED_FLASHBACK_SIZE from v$flashback_database_log;

oldest oldest

flashback flashback RETENTION FLASHBACKt ESTIMATED

scn# time# TARGET SIZE FLASHBACK_SIZE

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

1471397 2011-12-03 15:04:43 1440 47824896 0

关闭数据库，两个节点执行就可以了

SQL>shutdown immediate;

在rac1执行,启动到mount状态

SQL> startup mount;

SQL> flashback database to timestamp to_date('2011-12-03 15:38:27', 'yyyy-mm-dd hh24:mi:ss');

以read only打开数据库，看表是否回来了

SQL> alter database open read only;

SQL> conn jscn/jscn

SQL> desc test;

ERROR:

ORA-04043: object test does not exist

没回来，再来一次

SQL> shutdown immediate;

SQL> startup mount;

SQL> flashback database to timestamp to_date('2011-12-03 15:34:27', 'yyyy-mm-dd hh24:mi:ss');

SQL> alter database open read only;

SQL> select count(*) from test;

COUNT(*)

----------

148

SQL> shutdown immediate;

SQL> startup mount;

SQL> alter database open resetlogs;

为了保证数据的一致性，数据库要以resetlogs方式打开。

rac2上也开始实例

SQL> startup

或者基于scn号

SQL>flashback database to scn 5342420;

下同上