A control file contains information about the associated database that is required for access by an instance, both at startup and during normal operation. Control file information can be modified only by Oracle Database; no database administrator or user can edit a control file. It contains (but is not limited to) the following types of information :
- Database information (RESETLOGS SCN and their time stamp)
- Archive log history
- Tablespace and datafile records (filenames, datafile checkpoints, read/write status, offline or not).
- Redo threads (current online redo log)
- Database's creation date
- database name
- current archive log mode
- Log records (sequence numbers, SCN range in each log)
- RMAN catalog
- Database block corruption information
- Database ID, which is unique to each DB.
Size of control files :
The size of the control files is governed by the following parameters
- maxlogfiles
- maxlogmembers
- maxloghistory
- maxinstances
- control_file_record_keep_time
The controlfile contains the following sections:
Archives Log (reusable)
Backup Corruption (reusable)
Backup Datafile (reusable)
Backup Piece (reusable)
Backup Redolog (reusable)
Backuo Set (reusable)
Backup spfile
CKPT Process
Copy Corruption (reusable)
Datafile
Datafile Copy (reusable)
Datafile History
Database Incarnation
Deleted Objects (reusable)
Filename
Flashback Log
Instance Space Reservation
Log History (reusable)
MTTR
Offline Range (reusable)
Recovery Destination
Removable Recovery Files
Rman Status
Rman Configuration
Redo Threads
Redo Logs
Tablespace
Temporary Filename
Thread Instance Name Mapping
Proxy Copy
The minimum number of days that a reusable record is kept in the controlfile is controlled by the control_file_record_keep_time parameter. These sections consist of records. The size, total number and number of used record are exposed through v$controlfile_record_section.
SQL> alter database backup controlfile to trace as 'C:\CREATE_CONTROL.sql' ;
Enjoy :-)
2 comments:
what is the difference between reuseable and non reuseable sections ????
Difference between reuseable and non reusable section of control file
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