Oracle闪回详解管理

(4)确定闪回开启

咱俩发现在ARC方式下,打印出来的结果并不是NSStackBlock那些类型,很两人以为在ARC情势下block的花色唯有NSGlobalBlock和NSMallocBlock三种,其实那种观点是一无可取的。在ARC意况下,生成的block也是NSStackBlock,只是当赋值给strong对象时,系统会主动对其进展copy:

e.闪回快照

iOS开发中不时会接纳block结合gcd来成功十六线程编程,block也属于对象,主要有三种档次:
1、 _NSConcreteStackBlock ,存储在栈上;
2、_NSConcreteGlobalBlock,存储在程序的数码区域(text段);
3、_NSConcreteMallocBlock,存储在堆上。
下边分别介绍一下那三种档次的block,block在arc和非arc的形式下会有些需求小心的地点:

(5)关闭闪回

在example_addBlockToArray函数中添加的block由于为栈block,因而在example函数中调用的话会招致程序crash掉,可以经过将block拷贝到堆上来解决这些题材:

闪回级别 闪回场景 闪回技术 对象依赖   影响数据
数据库 表截断、逻辑错误、其他多表意外事件 闪回DATABASE 闪回日志、undo
DROP 删除表 闪回DROP 回收站(recyclebin)
更新、删除、插入记录 闪回TABLE 还原数据,undo
查询 当前数据和历史数据对比 闪回QUERY 还原数据,undo
版本查询 比较行版本 闪回Version Query 还原数据,undo
事务查询 比较 闪回Transaction Query 还原数据,undo
归档 DDL、DML 闪回Archive 归档日志
         
 [array addObject:[[^{
        printf("%cn", b);
    } copy autorelease]]];

(4)闪回数据库(truncate/多表数据变动)

此成效在11GR2格外实用,可机关创造闪回点、开启闪回日志,可形成线上数据测试后,然后做数据库闪回恢复生机主备关系

    int base = 100;
    long (^stackBlock) (int, int) = ^ long (int a, int b) {
        return base +a + b;
    };
    NSLog(@"%@",stackBlock);//<__NSStackBlock__: 0x7fff57c6bce0>

 二、Oracle闪回使用详解

    int i=0;
    NSLog(@"%@", ^{
        NSLog(@"stack block here, i=%d", i);
    });//<__NSStackBlock__: 0x7fff592eacf8>

    void (^block)()=^{
        NSLog(@"stack block here, i=%d", i);
    };
    NSLog(@"%@",block);//<__NSMallocBlock__: 0x7fae49e02660>

(7)闪回语句

  • NSGlobalBlock:在block内部没有引用任何外部变量

1、闪回开启
(1)开启闪回要求条件
a.开启归档日志

SQL> archive log list;
Database log mode Archive Mode
Automatic archival Enabled
Archive destination /home/U01/app/oracle/oradata/testdb/arch
Oldest online log sequence 844
Next log sequence to archive 846
Current log sequence 846

##如未开启,在mount状态执行alter database archivelog;
    int base = 100;
    long (^stackBlock) (int, int) = ^ long (int a, int b) {
        return base +a + b;
    };
    NSLog(@"%@",stackBlock);//<__NSMallocBlock__: 0x7f8da961e590>

Oracle 9i
早先援助闪回,Oracle10g开班周详帮衬闪回功用,Oracle11g有所完善,为我们神速的復苏数据,查询历史数据提供了很大的方便方式。

对NSGlobalBlock的retain、copy、release操作都不算。

2、闪回使用

    void example_addBlockToArray(NSMutableArray *array) {
      char b = 'B';
      [array addObject:^{
        printf("%cn", b);
      }];
    }

    void example() {
      NSMutableArray *array = [NSMutableArray array];
      example_addBlockToArray(array);
      void (^block)() = [array objectAtIndex:0];
      block();
    }

 

    void (^globalBlock) () = ^ () {
          NSLog(@"global block");
    };
    NSLog(@"%@", globalBlock);//<__NSGlobalBlock__: 0x1096e20c0>

但一旦两次三番覆盖,就要求指定復苏的表名,假设已经存在表,则须求还原重命名。

retain、release这体系型的block不起功能。下边看看在ARC情势下会有甚不一样的地点:

管理, c.闪回snapshot standby

  • NSMallocBlock
    一经NSStackBlock必要在其功能域外部使用的时候,在MRC的形式下须要手动将其copy到堆上,NSMallocBlock协理retain、release,会对其引用计数+1或-1,copy不会转移新的目的,只是增添了一遍引用,类似retain;而在ARC方式下会自动对其进展copy,不需求团结手动去管理,尽可能使用ARC。

  create restore point before_201712151111 guarantee flashback
database;

栈block在当函数退出的时候,该空间就会被回收,由此只要再调用该block会招致crash:

c.闪回事情查询
用来提供查看工作级别数据库变化的章程

  • NSStackBlock:在block内部引用外部变量
    先研商下MRC形式:
SQL> select * from V$FLASHBACK_DATABASE_LOG;

OLDEST_FLASHBACK_SCN OLDEST_FLASHBACK_TI RETENTION_TARGET FLASHBACK_SIZE ESTIMATED_FLASHBACK_SIZE
-------------------- ------------------- ---------------- -------------- ------------------------
16801523 2017-12-14 11:35:05 4320 104857600 244113408

  flashback database to restore point before_201712151111;

SQL> show recyclebin;
ORIGINAL NAME RECYCLEBIN NAME OBJECT TYPE DROP TIME
---------------- ------------------------------ ------------ -------------------
T BIN$YEh2QcvddJLgUxyAgQpnVQ==$0 TABLE 2017-12-14:15:07:54
T BIN$YEh2QcvcdJLgUxyAgQpnVQ==$0 TABLE 2017-12-14:15:07:27
SQL> flashback table "BIN$YEh2QcvcdJLgUxyAgQpnVQ==$0" to before drop ;
Flashback complete.
SQL> show recyclebin;
ORIGINAL NAME RECYCLEBIN NAME OBJECT TYPE DROP TIME
---------------- ------------------------------ ------------ -------------------
T BIN$YEh2QcvddJLgUxyAgQpnVQ==$0 TABLE 2017-12-14:15:07:54
SQL> flashback table t to before drop rename to tt;
Flashback complete.

(5)闪回归档(增添、修改、重命名、删除表的列、truncate表、修改表的封锁、以及修改分区表的分区规范)

SQL> flashback table scott.dept to timestamp to_timestamp('2017-12-14 16:20:00','yyyy-mm-dd hh24:mi:ss');
flashback table scott.dept to timestamp to_timestamp('2017-12-14 16:20:00','yyyy-mm-dd hh24:mi:ss')
ERROR at line 1:
ORA-08189: cannot flashback the table because row movement is not enabled

SQL> select row_movement from dba_tables where table_name='DEPT' and owner='SCOTT';
ROW_MOVE
--------
DISABLED
SQL> alter table scott.dept enable row movement;
Table altered.

SQL> flashback table scott.dept to timestamp to_timestamp('2017-12-14 16:20:00','yyyy-mm-dd hh24:mi:ss');
Flashback complete.
SQL> select * from scott.dept;
DEPTNO DNAME LOC
---------- -------------- -------------
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 SALES CHICAGO
40 OPERATIONS BOSTON    
SQL> alter table scott.dept disable row movement;
Table altered.

(6)查看闪回restore_point

SQL> select * from V$flashback_database_stat;
BEGIN_TIME END_TIME FLASHBACK_DATA DB_DATA REDO_DATA ESTIMATED_FLASHBACK_SIZE
------------------- ------------------- -------------- ---------- ---------- ------------------------
2017-12-14 14:34:53 2017-12-14 14:56:43 1703936 9977856 1487872 0    

 

(1)闪回查询
闪回查询首假如基于Undo表空间数据进行多版本查询,针对v$和x$动态性能视图无效,但对DBA_、ALL_、USER_是可行的
a.闪回查询
允许用户查询过去某个时间点的数码,用以重构由于意外删除或改动的数额,数据不会扭转。

当一个表被drop掉,表会被放入recyclebin回收站,可透过回收站做表的闪回。表上的目录、约束等一样会被还原
不匡助sys/system用户表空间对象,可由此alter system set
recyclebin=off;关闭回收站作用
闪回DROP示例:

(2)获取当前数据库的系统时间和SCN

(7)闪回空间爆满问题处理

SQL> select * from scott.dept;
DEPTNO DNAME LOC
---------- -------------- -------------
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 SALES CHICAGO
40 OPERATIONS BOSTON
SQL> delete from scott.dept where deptno=40;
1 row deleted.
SQL> commit;
Commit complete.
SQL> select * from scott.dept as of timestamp sysdate-10/1440;

DEPTNO DNAME LOC
---------- -------------- -------------
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 SALES CHICAGO
40 OPERATIONS BOSTON
SQL> select * from scott.dept as of timestamp to_timestamp('2017-12-14 16:20:00','yyyy-mm-dd hh24:mi:ss');

DEPTNO DNAME LOC
---------- -------------- -------------
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 SALES CHICAGO
40 OPERATIONS BOSTON

SQL> select * from scott.dept as of scn 16801523;

DEPTNO DNAME LOC
---------- -------------- -------------
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 SALES CHICAGO
40 OPERATIONS BOSTON
SQL> select * from t ;

ID NAME
---------- ---------------------------------------
1
2
3
4
30

SQL> drop table t;

Table dropped.

SQL> show recyclebin;
ORIGINAL NAME RECYCLEBIN NAME OBJECT TYPE DROP TIME
---------------- ------------------------------ ------------ -------------------
T BIN$YEh2QcvZdJLgUxyAgQpnVQ==$0 TABLE 2017-12-14:15:02:06
SQL> flashback table t to before drop;

Flashback complete.

SQL> select * from t;

ID NAME
---------- -------------------------------------
1
2
3
4
30    

数据库闪回必须在mounted状态下展开,基于快照的可以再open下展开闪回库
闪回数据库重点是将数据库还原值过去的某部时刻点或SCN,用于数据库出现逻辑错误时,需求open
database resetlogs
a.全库闪回
数据库闪回示例

 

select scn, STORAGE_SIZE ,to_char(time,'yyyy-mm-dd hh24:mi:ss') time,NAME from v$restore_point;
select database_role,open_mode,db_unique_name,flashback_on from v$database;

SQL> set line 200;
SQL> set pagesize 2000;
SQL> select database_role,open_mode,db_unique_name,flashback_on from v$database;

DATABASE_ROLE    OPEN_MODE            DB_UNIQUE_NAME                 FLASHBACK_ON
---------------- -------------------- ------------------------------ ------------------
PHYSICAL STANDBY READ ONLY            testdbms                       NO


SQL> ALTER DATABASE CONVERT TO SNAPSHOT STANDBY;  

Database altered.

SQL> select database_role,open_mode,db_unique_name,flashback_on from v$database;

DATABASE_ROLE    OPEN_MODE            DB_UNIQUE_NAME                 FLASHBACK_ON
---------------- -------------------- ------------------------------ ------------------
SNAPSHOT STANDBY MOUNTED              testdbms                       RESTORE POINT ONLY

SQL> alter database open;

Database altered.

SQL> select open_mode from v$database;

OPEN_MODE
--------------------
READ WRITE


此时备库操作:
SQL> select * from scott.emp;

     EMPNO ENAME      JOB              MGR HIREDATE                   SAL       COMM     DEPTNO
---------- ---------- --------- ---------- ------------------- ---------- ---------- ----------
      7369 SMITH      CLERK           7902 1980-12-17 00:00:00        800                    20
      7499 ALLEN      SALESMAN        7698 1981-02-20 00:00:00       1600        300         30
      7521 WARD       SALESMAN        7698 1981-02-22 00:00:00       1250        500         30
      7566 JONES      MANAGER         7839 1981-04-02 00:00:00       2975                    20
      7654 MARTIN     SALESMAN        7698 1981-09-28 00:00:00       1250       1400         30
      7698 BLAKE      MANAGER         7839 1981-05-01 00:00:00       2850                    30
      7782 CLARK      MANAGER         7839 1981-06-09 00:00:00       2450                    10
      7788 SCOTT      ANALYST         7566 1987-04-19 00:00:00       3000                    20
      7839 KING       PRESIDENT            1981-11-17 00:00:00       5000                    10
      7844 TURNER     SALESMAN        7698 1981-09-08 00:00:00       1500          0         30
      7876 ADAMS      CLERK           7788 1987-05-23 00:00:00       1100                    20
      7900 JAMES      CLERK           7698 1981-12-03 00:00:00        950                    30
      7902 FORD       ANALYST         7566 1981-12-03 00:00:00       3000                    20
      7934 MILLER     CLERK           7782 1982-01-23 00:00:00       1300                    10

14 rows selected.

SQL> truncate table scott.emp;

Table truncated.

主库操作:
SQL> create table scott.t as select * from scott.dept;

Table created.

SQL> select * from scott.t;

    DEPTNO DNAME          LOC           ADDR
---------- -------------- ------------- ------------------------------
        10 ACCOUNTING     NEW YORK
        20 RESEARCH       DALLAS
        30 SALES          CHICAGO

备库恢复到物理standby
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.

Total System Global Area 9.4067E+10 bytes
Fixed Size                  2263936 bytes
Variable Size            9663677568 bytes
Database Buffers         8.4289E+10 bytes
Redo Buffers              112766976 bytes
Database mounted.
SQL> ALTER DATABASE CONVERT TO PHYSICAL STANDBY; 

Database altered.
SQL> shutdown immediate;
ORA-01507: database not mounted


ORACLE instance shut down.
SQL> startup ;
ORACLE instance started.

Total System Global Area 9.4067E+10 bytes
Fixed Size                  2263936 bytes
Variable Size            9663677568 bytes
Database Buffers         8.4289E+10 bytes
Redo Buffers              112766976 bytes
Database mounted.
Database opened.

##此时备库的数据已经恢复到转变snapshot standby时间点
SQL> select database_role,open_mode,db_unique_name,flashback_on from v$database;

DATABASE_ROLE    OPEN_MODE            DB_UNIQUE_NAME                 FLASHBACK_ON
---------------- -------------------- ------------------------------ ------------------
PHYSICAL STANDBY READ ONLY            testdbms                       NO

SQL>  select * from scott.emp;

     EMPNO ENAME      JOB              MGR HIREDATE                   SAL       COMM     DEPTNO
---------- ---------- --------- ---------- ------------------- ---------- ---------- ----------
      7369 SMITH      CLERK           7902 1980-12-17 00:00:00        800                    20
      7499 ALLEN      SALESMAN        7698 1981-02-20 00:00:00       1600        300         30
      7521 WARD       SALESMAN        7698 1981-02-22 00:00:00       1250        500         30
      7566 JONES      MANAGER         7839 1981-04-02 00:00:00       2975                    20
      7654 MARTIN     SALESMAN        7698 1981-09-28 00:00:00       1250       1400         30
      7698 BLAKE      MANAGER         7839 1981-05-01 00:00:00       2850                    30
      7782 CLARK      MANAGER         7839 1981-06-09 00:00:00       2450                    10
      7788 SCOTT      ANALYST         7566 1987-04-19 00:00:00       3000                    20
      7839 KING       PRESIDENT            1981-11-17 00:00:00       5000                    10
      7844 TURNER     SALESMAN        7698 1981-09-08 00:00:00       1500          0         30
      7876 ADAMS      CLERK           7788 1987-05-23 00:00:00       1100                    20
      7900 JAMES      CLERK           7698 1981-12-03 00:00:00        950                    30
      7902 FORD       ANALYST         7566 1981-12-03 00:00:00       3000                    20
      7934 MILLER     CLERK           7782 1982-01-23 00:00:00       1300                    10

14 rows selected.


SQL> alter database recover managed standby database using current logfile disconnect;

Database altered.

SQL> select * from scott.t;

    DEPTNO DNAME          LOC           ADDR
---------- -------------- ------------- ------------------------------
        10 ACCOUNTING     NEW YORK
        20 RESEARCH       DALLAS
        30 SALES          CHICAGO


SQL>  select database_role,open_mode,db_unique_name,flashback_on from v$database;

DATABASE_ROLE    OPEN_MODE            DB_UNIQUE_NAME                 FLASHBACK_ON
---------------- -------------------- ------------------------------ ------------------
PHYSICAL STANDBY READ ONLY WITH APPLY testdbms                       NO

b.设置合理的闪回区

select scn,to_char(time_dp,'yyyy-mm-dd hh24:mi:ss')from sys.smon_scn_time;
SQL> select flashback_on from v$database;
FLASHBACK_ON
------------------
NO

 

 

 

SQL> select flashback_on from v$database;
FLASHBACK_ON
------------------
YES    

(5)SCN和timestamp装换关系查询

用来查询行级数据库随时间变化的法门

(2)闪回表(update/insert/delete)
闪回表就是对表的数目做回退,回退到前边的某部时间点,其使用的是undo的历史数据,与undo_retention设置有关,默许是14400分钟(1天)
一样,sys用户表空间不协理闪回表,要想表闪回,须求允许表启动行迁移(row
movement)
闪回表示例:

三、备注
1、相关数据字典
V$FLASHBACK_DATABASE_LOG ##查阅数据库可闪回的时间点/SCN等音信
V$flashback_database_stat ##翻开闪回日志空间记录信息
2、常用查询语句
(1)查看数据库状态

(7)主库做库的闪回,会影响备库,必要再度联合
(8)snapshot standby 不扶助最高尊崇格局

 针对主库和备库都足以创制闪回快照点,然后还原到指定的快照点,但主库一旦苏醒到快照点,备库的一头则需求重新联合

(3)开启闪回

SQL> alter database flashback off;
Database altered.

一、Oracle闪回概述

 

SQL> alter system set db_recovery_file_dest='/home/U01/app/oracle/fast_recovery_area' scope=both;
System altered.
SQL> alter system set db_recovery_file_dest_size=60G scope=both;
System altered.
SQL> alter system set db_flashback_retention_target=4320 scope=both;
System altered.    

a.开启归档

a.闪回数据库
  FLASHBACK DATABASE TO TIMESTAMP to_timestamp(‘2017-12-14
14:28:33′,’yyyy-mm-dd HH24:MI:SS’);;
  flashback database to scn 16813234;
b.闪回DROP
其中table_name能够是删除表名称,也可以是别名
  flashback table table_name to before drop;
  flashback table table_name to before drop rename to
table_name_new;
c.闪回表
  flashback table table_name to scn scn_number;
  flashback table table_name to timestamp to_timestamp(‘2017-12-14
14:28:33′,’yyyy-mm-dd hh24:mi:ss’);
d.闪回查询
  select * from table_name as of timestamp to_timestamp(‘2017-12-14
14:28:33′,’yyyy-mm-dd hh24:mi:ss’);
  select * from scott.dept as of scn 16801523;

SQL> select NAME,OPEN_MODE ,DATABASE_ROLE,CURRENT_SCN,FLASHBACK_ON from v$database;

NAME OPEN_MODE DATABASE_ROLE CURRENT_SCN FLASHBACK_ON
------------- -------------------- ---------------- ----------- ------------------
TESTDB READ WRITE PRIMARY 16812246 YES

(4)查看闪回日志空间情况

db_recovery_file_dest:指定闪回过来区的地点
db_recovery_file_dest_size:指定闪回过来区的可用空间大小
db_flashback_retention_target:指定数据库可以回退的光阴,单位为分钟,默认1440分钟(1天),实际取决于闪回区大小
(2)检查是否打开闪回

3、闪回注意事项
(1)数据库闪回须求在mounted下展开,并且open时索要采纳resetlogs
(2)闪回DROP只好用于非系统表空间和地点管理的表空间,外键约束不能复苏,对方覆盖、重命名需注意
(3)表DROP,对应的物化视图会被彻底去除,物化视图不会存放在recyclebin里
(4)闪回表,即便在做过dml,然后开展了表结构修改、truncate等DDL操作,新增/删除结构无法做闪回
(5)闪回归档,必须在assm管理tablespace和undo auto管理下进展
(6)注意闪回区管理,幸免磁盘爆满,闪回区空间欠缺等

b.快照闪回

 

 

SQL> select * from scott.dept;

    DEPTNO DNAME          LOC           ADDR
---------- -------------- ------------- ------------------------------
        10 ACCOUNTING     NEW YORK
        20 RESEARCH       DALLAS
        30 SALES          CHICAGO

SQL> create restore point before_201712151111 guarantee flashback database;
Restore point created.

SQL> create table scott.t as select * from scott.dept;
Table created.

SQL> truncate table scott.t;
Table truncated.
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.

Total System Global Area 9.4067E+10 bytes
Fixed Size                  2263936 bytes
Variable Size            9663677568 bytes
Database Buffers         8.4289E+10 bytes
Redo Buffers              112766976 bytes
Database mounted.
SQL> flashback database to restore point before_201712151111;
Flashback complete.
SQL> alter database open resetlogs;
Database altered.

此时主库scott.t已不存在:
SQL> select * from scott.t;
select * from scott.t
                    *
ERROR at line 1:
ORA-00942: table or view does not exist
此时从库的scott.依旧存在,主备同步终止
解决方案:在主库创建快照时间点,从库自动停止应用日志,等主库闪回后,重新应用日志即可。
如果已经做了上述操作,从库可以选择重建
ALTER DATABASE REGISTER LOGFILE '/xx/xx/archive.dbf';
SQL> select to_char(systimestamp,'yyyy-mm-dd HH24:MI:SS') as sysdt , dbms_flashback.get_system_change_number scn from dual;

SYSDT SCN
------------------- ----------
2017-12-14 14:28:33 16813234

b.闪回版本查询

(3)查看数据库可复原的年华点

select scn, STORAGE_SIZE ,to_char(time,'yyyy-mm-dd hh24:mi:ss') time,NAME from v$restore_point;

请参考我前面的博客园:http://blog.itpub.net/27067062/viewspace-2129130/

  

本文紧要对Oracle常用闪回使用做些详细介绍,其中对于不常用的业务和版本闪回,那里就不做牵线

SQL> select * from scott.EMP;

EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- ---------- --------- ---------- ------------------- ---------- ---------- ----------
7369 SMITH CLERK 7902 1980-12-17 00:00:00 800 20
7499 ALLEN SALESMAN 7698 1981-02-20 00:00:00 1600 300 30
7521 WARD SALESMAN 7698 1981-02-22 00:00:00 1250 500 30
7566 JONES MANAGER 7839 1981-04-02 00:00:00 2975 20
7654 MARTIN SALESMAN 7698 1981-09-28 00:00:00 1250 1400 30
7698 BLAKE MANAGER 7839 1981-05-01 00:00:00 2850 30
7782 CLARK MANAGER 7839 1981-06-09 00:00:00 2450 10
7788 SCOTT ANALYST 7566 1987-04-19 00:00:00 3000 20
7839 KING PRESIDENT 1981-11-17 00:00:00 5000 10
7844 TURNER SALESMAN 7698 1981-09-08 00:00:00 1500 0 30
7876 ADAMS CLERK 7788 1987-05-23 00:00:00 1100 20
7900 JAMES CLERK 7698 1981-12-03 00:00:00 950 30
7902 FORD ANALYST 7566 1981-12-03 00:00:00 3000 20
7934 MILLER CLERK 7782 1982-01-23 00:00:00 1300 10

14 rows selected.

SQL> truncate table scott.EMP;

Table truncated.
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.

Total System Global Area 9.4067E+10 bytes
Fixed Size 2263936 bytes
Variable Size 9395242112 bytes
Database Buffers 8.4557E+10 bytes
Redo Buffers 112766976 bytes
Database mounted.
SQL> flashback database to timestamp to_timestamp('2017-12-14 14:12:46','yyyy-mm-dd HH24:MI:SS');

Flashback complete.
SQL> alter database open resetlogs;

Database altered.

SQL> select * from scott.emp;

EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- ---------- --------- ---------- ------------------- ---------- ---------- ----------
7369 SMITH CLERK 7902 1980-12-17 00:00:00 800 20
7499 ALLEN SALESMAN 7698 1981-02-20 00:00:00 1600 300 30
7521 WARD SALESMAN 7698 1981-02-22 00:00:00 1250 500 30
7566 JONES MANAGER 7839 1981-04-02 00:00:00 2975 20
7654 MARTIN SALESMAN 7698 1981-09-28 00:00:00 1250 1400 30
7698 BLAKE MANAGER 7839 1981-05-01 00:00:00 2850 30
7782 CLARK MANAGER 7839 1981-06-09 00:00:00 2450 10
7788 SCOTT ANALYST 7566 1987-04-19 00:00:00 3000 20
7839 KING PRESIDENT 1981-11-17 00:00:00 5000 10
7844 TURNER SALESMAN 7698 1981-09-08 00:00:00 1500 0 30
7876 ADAMS CLERK 7788 1987-05-23 00:00:00 1100 20
7900 JAMES CLERK 7698 1981-12-03 00:00:00 950 30
7902 FORD ANALYST 7566 1981-12-03 00:00:00 3000 20
7934 MILLER CLERK 7782 1982-01-23 00:00:00 1300 10

14 rows selected.
SQL> alter database flashback on;
Database altered.

 

b.设置闪回区

 

c.开启flashback (10g在mount开启)

mount状态:alter database archivelog;

(3)闪回DROP(drop table)

备考:即便不初阶flashback,只要打开了recyclebin,那么就足以闪回DROP表。

Post Author: admin

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