深入理解Javascript之执行上下文(Execution Context)

 RMAN备份方案
RMAN也可以进行联机备份，而且备份与恢复方法将比OS备份更简单可靠。
1、连接数据库，创建测试表并插入记录
SQL*Plus: Release 8.1.6.0.0 - Production on Tue May 6 13:46:32 2003
(c) Copyright 1999 Oracle Corporation. All rights reserved.
SQL> connect internal/password as sysdba;
Connected.

SQL> create table test(a int) tablespace users;
Table created
SQL> insert into test values(1);
1 row inserted
SQL> commit;
Commit complete

2、备份数据库表空间users
C:\> rman
Recovery Manager: Release 8.1.6.0.0 - Production
RMAN> connect rcvcat rman/rman@back
RMAN-06008: connected to recovery catalog database
RMAN> connect target internal/virpure
RMAN-06005: connected to target database: TEST (DBID=1788174720)

RMAN> run{
2> allocate channel c1 type disk;
3> backup tag 'tsuser ' format 'd:\backup\tsuser_%u_%s_%p '
4> tablespace users;
5> release channel c1;
6> }

RMAN-03022: compiling command: allocate
RMAN-03023: executing command: allocate
RMAN-08030: allocated channel: c1
RMAN-08500: channel c1: sid=16 devtype=DISK

RMAN-03022: compiling command: backup
RMAN-03025: performing implicit partial resync of recovery catalog
RMAN-03023: executing command: partial resync
RMAN-08003: starting partial resync of recovery catalog
RMAN-08005: partial resync complete
RMAN-03023: executing command: backup
RMAN-08008: channel c1: starting full datafile backupset
RMAN-08502: set_count=5 set_stamp=494177612 creation_time=16-MAY-03
RMAN-08010: channel c1: specifying datafile(s) in backupset
RMAN-08522: input datafile fno=00003 name=D:\ORACLE\ORADATA\TEST\USER01.DBF
RMAN-08013: channel c1: piece 1 created
RMAN-08503: piece handle=D:\BACKUP\TSUSER_05EN93AC_5_1 comment=NONE
RMAN-08525: backup set complete, elapsed time: 00:00:01
RMAN-03023: executing command: partial resync
RMAN-08003: starting partial resync of recovery catalog
RMAN-08005: partial resync complete
RMAN-03022: compiling command: release
RMAN-03023: executing command: release
RMAN-08031: released channel: c1
RMAN>

3、继续在测试表中插入记录
SQL> insert into test values(2);
1 row inserted
SQL> commit;
Commit complete
SQL> select * from test;
A
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1
2
SQL> alter system switch logfile;
System altered.
SQL> r
1* alter system switch logfile;
System altered.

4、关闭数据库，模拟丢失数据文件
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down

C:\> del D:\ORACLE\ORADATA\TEST\USER01.DBF

5、启动数据库，检查错误
SQL> startup
ORACLE instance started.
Total System Global Area 102020364 bytes
Fixed Size 70924 bytes
Variable Size 85487616 bytes
Database Buffers 16384000 bytes
Redo Buffers 77824 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 3 - see DBWR trace file
ORA-01110: data file 3: 'D:\ORACLE\ORADATA\TEST\USER01.DBF '

6、先打开数据库
SQL> alter database datafile 3 offline drop;
Database altered.
SQL> alter database open;
Database altered.

7、恢复该表空间
恢复脚本可以是恢复单个数据文件
run{
allocate channel c1 type disk;
restore datafile 3;
recover datafile 3;
sql 'alter database datafile 3 online ';
release channel c1;
}
也可以是,恢复表空间
run{
allocate channel c1 type disk;
restore tablespace users;
recover tablespace users;
sql 'alter database datafile 3 online ';
release channel c1;
}
过程如下：
C:\> rman
Recovery Manager: Release 8.1.6.0.0 - Production
RMAN> connect rcvcat rman/rman@back
RMAN-06008: connected to recovery catalog database
RMAN> connect target internal/virpure
RMAN-06005: connected to target database: TEST (DBID=1788174720)

RMAN> run{
2> allocate channel c1 type disk;
3> restore datafile 3;
4> recover datafile 3;
5> sql 'alter database datafile 3 online ';
6> release channel c1;
7> }

RMAN-03022: compiling command: allocate
RMAN-03023: executing command: allocate
RMAN-08030: allocated channel: c1
RMAN-08500: channel c1: sid=13 devtype=DISK
RMAN-03022: compiling command: restore
RMAN-03022: compiling command: IRESTORE
RMAN-03023: executing command: IRESTORE
RMAN-08016: channel c1: starting datafile backupset restore
RMAN-08502: set_count=5 set_stamp=494177612 creation_time=16-MAY-03
RMAN-08089: channel c1: specifying datafile(s) to restore from backup set
RMAN-08523: restoring datafile 00003 to D:\ORACLE\ORADATA\TEST\USER01.DBF
RMAN-08023: channel c1: restored backup piece 1
RMAN-08511: piece handle=D:\BACKUP\TSUSER_05EN93AC_5_1 tag=TSUSER params=NULL
RMAN-08024: channel c1: restore complete
RMAN-03023: executing command: partial resync
RMAN-08003: starting partial resync of recovery catalog
RMAN-08005: partial resync complete
RMAN-03022: compiling command: recover
RMAN-03022: compiling command: recover(1)
RMAN-03022: compiling command: recover(2)
RMAN-03022: compiling command: recover(3)
RMAN-03023: executing command: recover(3)
RMAN-08054: starting media recovery
RMAN-03022: compiling command: recover(4)
RMAN-06050: archivelog thread 1 sequence 332 is already on disk as file D:\ORACLE\ORADATA\TEST\ARCHIVE\TESTT001S00332.ARC
RMAN-06050: archivelog thread 1 sequence 333 is already on disk as file D:\ORACLE\ORADATA\TEST\ARCHIVE\TESTT001S00333.ARC
RMAN-06050: archivelog thread 1 sequence 334 is already on disk as file D:\ORACLE\ORADATA\TEST\ARCHIVE\TESTT001S00334.ARC
RMAN-03023: executing command: recover(4)
RMAN-08515: archivelog filename=D:\ORACLE\ORADATA\TEST\ARCHIVE\TESTT001S00332.ARC thread=1 sequence=332
RMAN-08055: media recovery complete
RMAN-03022: compiling command: sql
RMAN-06162: sql statement: alter database datafile 3 online
RMAN-03023: executing command: sql
RMAN-03022: compiling command: release
RMAN-03023: executing command: release
RMAN-08031: released channel: c1
RMAN>

8、检查数据是否完整
SQL> alter database open;
Database altered.

SQL> select * from test;
A
---------------------------------------
1
2
说明：
1、RMAN也可以实现单个表空间或数据文件的恢复，恢复过程可以在mount下或open方式下，如果在open方式下恢复，可以减少down机时间
2、如果损坏的是一个数据文件，建议offline并在open方式下恢复
3、这里可以看到，RMAN进行数据文件与表空间恢复的时候，代码都比较简单，而且能保证备份与恢复的可靠性，所以建议采用RMAN的备份与恢复