oracle学习总结一（基础）

控制文件用于记录和维护数据库。当恢复数据库时，服务器进程和后台进程需要从控制文件中读取各种备份相关的信息。如果控制文件损坏，则会导致这些备份信息的丢失。尽管使用多元化控制文件可以防止控制文件损坏，但因为控制文件的重要性，应该定期备份控制文件。当数据库配置发生改变时，一定要备份控制文件。涉及到数据库配置改变的命令：

alter database [add|drop] logfile

alter database [add|drop] logfile member

alter database [add|drop] logfile group

alter database [noarchivelog|archivelog]

alter database rename file

create tablespace

alter tablespace [add|rename] datafile

alter tablespace [read write|read only]

drop tablespace

控制文件的备份,三种方式

1)使用OS命令进行拷贝

1)open状态下，使用alter database命令生成控制文件副本

2)open状态下，使用alter database backup controlfile to trace命令将控制文件备份到跟踪文件

控制文件的恢复,两种方式

1)mount状态下，使用RECOVER DATABASE USING BACKUP CONTROLFILE

2)mount状态下，生成跟踪文件并进行恢复

2--2示例：

[oracle@localhost ~]$ rlsqlplus / as sysdba

SQL*Plus: Release 10.2.0.1.0 - Production on 星期一 8月 1 21:40:03 2011

Copyright (c) 1982, 2005, Oracle. All rights reserved.

Connected to an idle instance.

SQL> startup

ORACLE instance started.

Total System Global Area 528482304 bytes

Fixed Size 1220360 bytes

Variable Size 176161016 bytes

Database Buffers 343932928 bytes

Redo Buffers 7168000 bytes

Database mounted.

Database opened.
--open状态下生成控制文件副本

SQL> alter database backup controlfile to

2 '/oracle/10g/oracle/bakup/database/oralife.ctl';

alter database backup controlfile to

*

ERROR at line 1:

ORA-01580: error creating control backup file

/oracle/10g/oracle/bakup/database/oralife.ctl

ORA-27038: created file already exists

Additional information: 1

SQL> alter database backup controlfile to

2 '/oracle/10g/oracle/bakup/database/oralife.ctl' reuse;
--reuse用于覆盖原有控制文件副本

Database altered.

--手动删除所有控制文件模拟文件丢失

SQL> ho rm /oracle/10g/oracle/product/10.2.0/oradata/oralife/*.ctl;

--使用evan登录，并添加数据

SQL> conn evan/evan

Connected.

SQL> select * from t_evan;

TEXT

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

oracle

java

spring

hibernate

hibernate

SQL> insert into t_evan values('added');

1 row created.

SQL> commit;

Commit complete.

SQL> conn / as sysdba

Connected.

SQL> shutdown immediate

ORA-00210: cannot open the specified control file

ORA-00202: control file: '/oracle/10g/oracle/product/10.2.0/oradata/oralife/control01.ctl'

ORA-27041: unable to open file

Linux Error: 2: No such file or directory

Additional information: 3

SQL> shutdown abort

ORACLE instance shut down.

--alter_oralife.log出现这样的信息：

Mon Aug 1 23:13:51 2011

ORA-00202: control file: '/oracle/10g/oracle/product/10.2.0/oradata/oralife/control01.ctl'

ORA-27037: unable to obtain file status

Linux Error: 2: No such file or directory

Additional information: 3

--拷贝控制文件到目标路径

SQL>ho cp /oracle/10g/oracle/bakup/database/oralife.ctl /oracle/10g/oracle/product/10.2.0/oradata/oralife/control01.ctl

SQL> alter system set control_files='/oracle/10g/oracle/product/10.2.0/oradata/oralife/control01.ctl' scope = spfile;--修改control_files参数，指定可用的控制文件

System altered.

SQL> startup force mount

ORACLE instance started.

Total System Global Area 528482304 bytes

Fixed Size 1220360 bytes

Variable Size 138412280 bytes

Database Buffers 381681664 bytes

Redo Buffers 7168000 bytes

Database mounted.
--生成trace文件

SQL> alter database backup controlfile to trace noresetlogs;

Database altered.

SELECT c.VALUE || '/' || d.instance_name || '_ora_' || a.spid || '.trc' TRACE

FROM v$process a, v$session b, v$parameter c, v$instance d

WHERE a.addr = b.paddr

AND b.audsid = USERENV ('sessionid')

AND c.NAME = 'user_dump_dest';

TRACE

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

/oracle/10g/oracle/product/10.2.0/db_1/admin/oralife/udump/oralife_ora_4558.trc

SQL> shutdown immediate

ORA-01109: database not open

Database dismounted.

ORACLE instance shut down.

--打开trace文件，去掉注释，在shutdown状态下执行脚本，创建控制文件

--用evan登录验证数据

SQL> conn evan/evan

Connected.

SQL> select * from t_evan;

TEXT

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

oracle

java

spring

hibernate

hibernate

added

6 rows selected.

可见数据没有丢失。

SQL> select name from v$controlfile;

NAME

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

/oracle/10g/oracle/product/10.2.0/oradata/oralife/control01.ctl

这时应该重建多个控制文件。

如何做？
--设置control_files参数，前提是使用spfile启动数据库

SQL> show parameter spfile

NAME TYPE VALUE

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

spfile string /oracle/10g/oracle/product/10.
2.0/db_1/dbs/spfileoralife.ora

SQL> select name from v$controlfile;

NAME

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

/oracle/10g/oracle/product/10.2.0/oradata/oralife/control01.ctl

SQL> alter system set control_files='/oracle/10g/oracle/product/10.2.0/oradata/oralife/control01.ctl'

2 ,'/oracle/10g/oracle/product/10.2.0/oradata/oralife/control02.ctl'

3 ,'/oracle/10g/oracle/product/10.2.0/oradata/oralife/control03.ctl'

4 scope=spfile;

System altered.

SQL> shutdown immediate

Database closed.

Database dismounted.

ORACLE instance shut down.
--拷贝控制文件到不同的磁盘

SQL> host

[oracle@localhost oralife]$ cp control01.ctl control02.ctl

[oracle@localhost oralife]$ cp control01.ctl control03.ctl

[oracle@localhost ~]$ rlsqlplus / as sysdba

SQL*Plus: Release 10.2.0.1.0 - Production on 星期二 8月 2 21:02:57 2011

Copyright (c) 1982, 2005, Oracle. All rights reserved.

Connected to an idle instance.

SQL> startup

ORACLE instance started.

Total System Global Area 528482304 bytes

Fixed Size 1220360 bytes

Variable Size 142606584 bytes

Database Buffers 377487360 bytes

Redo Buffers 7168000 bytes

Database mounted.

Database opened.

SQL> select name from v$controlfile;

NAME

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

/oracle/10g/oracle/product/10.2.0/oradata/oralife/control01.ctl

/oracle/10g/oracle/product/10.2.0/oradata/oralife/control02.ctl

/oracle/10g/oracle/product/10.2.0/oradata/oralife/control03.ctl

已生效。