Controll File

[Former Member]

hi all,

May i know what confroll file contents.

with regard,

Harish Reddy

[Former Member]

Hi

Control files :

The control files of a database store the status of the physical structure of the database. The control file is absolutely crucial to database operation. 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

The location of the control files is specified through the control_files init param.

Backing up Controlfiles

When a controlfile (multiplexed or not) becomes unavailable (because for example of a media failure, the database cannot continue to operate. Because control files keep track of datafiles the control file should be backed up whenever a change is made to the database (alter database). The command to back the control file up is: alter database backup controlfile to 'filename'.

Recovering database when controlfile is lost

If the controlfile is lost, it is somewhat difficult to do a recovery because the database cannot be mounted for a recovery. The controlfile must be recreated (with create controlfile whose syntax is a bit awkyard. In order to recover from a lost spfile, the DBID is required.

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

Sections

The controlfile contains the following sections:

ARCHIVED LOG (reusable)

BACKUP CORRUPTION (reusable)

BACKUP DATAFILE (reusable)

BACKUP PIECE (reusable)

BACKUP REDOLOG (reusable)

BACKUP SET (reusable)

BACKUP SPFILE

CKPT PROGRESS

COPY CORRUPTION (reusable)

DATABASE

DATAFILE

DATAFILE COPY (reusable)

DATAFILE HISTORY

DATABASE INCARNATION

DELETED OBJECT (reusable)

FILENAME

FLASHBACK LOG

INSTANCE SPACE RESERVATION

LOG HISTORY (reusable)

MTTR

OFFLINE RANGE (reusable)

RECOVERY DESTINATION

REMOVABLE RECOVERY FILES

RMAN STATUS

RMAN CONFIGURATION

REDO THREAD

REDO LOG

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.

IF YOU WANT MORE INFORMATION SEE THIS PATH

http://www.sap.com/search/index.epx?q1=control%20files

regards,

reddy