O r a l c e d B A training _ lesson06

Control File

-Small binary files

-Define the current status of the physical database

-The loss control file must be fixed.

-Maintain database integrity

-Requirements:

1. The database is in the mount state when it is started

2. Database Operations

-Only link to one database

-The size was initially determined by the create database.

 

Control File Content

The control file contains the following entries:

-Database Name and identifier

-Database creation Timestamp

-Tablespace name

-Name and location of the data file and redo log file

-Serial number of the current redo log

-Checkpoint Information

-Start and end of the restore segment

-Redo log archiving information

-Backup Information

 

Multiple backup of Control Files

Multiple backup of control files when using spfile

1. Modify the spfile

Alter system set control_files = '$ HOME/ORADATA/u01/ctrl01.ctl ',

'$ HOME/ORADATA/u02/ctrl02.ctl' SCOPE = SPFILE;

2. Shut down the database

Shutdown immediate

3. Create a control file copy

Cp $ HOME/ORADATA/u01/ctrl01.ctl $ HOME/ORADATA/u02/ctrl02.ctl

4. Start the database

Startup

 

Multiple backup of the control file when pfile is used

1. Close the database:

Shutdown immediate

2. Create a control file copy:

Cp $ HOME/ORADATA/u01/ctrl01.ctl $ HOME/ORADATA/u02/ctrl02.ctl

3. Add a control file name to pfile:

Control_files = (/disk1/control01.ctl,/disk2/contril02.ctl)

4. Start the database

Startup

 

Use OMF to manage control files

-If the control_files parameter is not specified, OMF is created.

-The location is specified by DB_CREATE_ONLINE_LOG_DEST_n.

-The generated name is unique and displayed in alertSID. log.

 

Obtain Control File Information

You can query the status and location information of the control file in the following view.

-V $ controlfile: lists the names and statuses of all control files associated with the instance.

-V $ parameter: lists the statuses and locations of all parameters.

-V $ controlfile_record_section: provides information about the control file record.

-Show parameter control_files: lists the name, status, and location of the control file.