oracle控制文件

查看控制文件的位置


show PARAMETER control_file;

select name,value from v$parameter
where name=‘control_files’;

select name,status from v$controlfile;

查看制文件内容
（一）strings /u01/app/oracle/oradata/cdb1/control01.ctl

二
alter database backup controlfile to trace as ‘/u01/ctl.txt’;

vim /u01/ctl.txt’

三
desc v$controlfile_record_section

select type,RECORD_SIZE from v$controlfile_record_section；

减少控制文件数量
先查看系统有多少个
show PARAMETERS control_f

ls /u01/app/oracle/oradata/cdb1/c*

alter system set control_files=’/u01/app/oracle/oradata/cdb1/control01.ctl’
scope=spfile;

shutdown immediate
startup nomount

show PARAMETERS control_f

增加控制文件
alter system set control_files=’/u01/app/oracle/oradata/cdb1/control01.ctl’,
‘/u01/app/oracle/oradata/cdb1/control02.ctl’,
‘/u01/app/oracle/oradata/cdb1/control03.ctl’
scope=spfile;

startup force

show PARAMETERS control_f

备份控制文件
在归档情况下

创建备份文件夹
ho mkdir /u01/app/back/
alter database backup controlfile to ‘/u01/app/back/control.bak’;

查看备份

重建控制文件
alter database backup controlfile to trace as ‘/u01/app/back/control.txt’;

查看创建

rman备份
rman target /
backup current controlfile;

配置控制文件自动备份

开启自动备份
CONFIGURE CONTROLFILE AUTOBACKUP on;

它会自动备份到这里

无法启动问题（两个控制文件记录内容不同）

解决办法，高版本替换低版本控制文件
ho cp /u01/app/oracle/oradata/cdb1/control01.ctl /u01/app/oracle/oradata/cdb1/control02.ctl

alter database open;

有备份的恢复
方法一
删除控制文件 rm /u01/app/oracle/oradata/cdb1/control*

shutdown immediate

shutdown abort

Startup

确认系统已经没有控制文件了
/u01/app/oracle/oradata/cdb1/c*

恢复
把文件拷贝回来，三个都要拷贝回来
ho cp /u01/app/back/control.bak /u01/app/oracle/oradata/cdb1/control01.ctl
ho cp /u01/app/back/control.bak /u01/app/oracle/oradata/cdb1/control02.ctl
ho cp /u01/app/back/control.bak /u01/app/oracle/oradata/cdb1/control03.ctl

查看拷贝回来的控制文件
ho ls /u01/app/oracle/oradata/cdb1/c*

alter database mount;

alter database open;

alter database open resetlogs;

alter database recover database using backup controlfile;

shutdown abort
startup

alter database open resetlogs;

recover database;

recover database using backup controlfile;
输入undo表空间路径，蒙
/u01/app/oracle/oradata/cdb1/redo01.log


蒙对了

alter database open;

alter database open resetlogs;

archive log list这里都会变成1

方法二
无法打开文件丢失

show PARAMETERS control_f

ho cp /u01/app/back/control.bak /u01/app/oracle/oradata/cdb1/control01.ctl
ho cp /u01/app/back/control.bak /u01/app/oracle/oradata/cdb1/control01.ctl
ho cp /u01/app/back/control.bak /u01/app/oracle/oradata/cdb1/control03.ctl
ho ls /u01/app/oracle/oradata/cdb1/c*

alter database mount;
alter database open;

recover database using backup controlfile;

recover database;

alter system set “_allow_resetlogs_corruption”=true scope=spfile;

startup force

alter database open resetlogs;

退出重新进入

archive log list

show parameter _allow_resetlogs_corruption

alter system reset “_allow_resetlogs_corruption” scope=spfile sid=’*’;

shutdown immediate
startup