What happens if control file is lost in Oracle?
If all control files have been lost in a permanent media failure, but all online redo log members remain intact, then you can recover the database after creating a new control file. You are not required to open the database with the RESETLOGS option after the recovery.
What is importance of control file in Oracle?
A control file tracks the physical components of the database. It is the root file that the database uses to find all the other files used by the database. Because of the importance of the control file, Oracle recommends that the control file be multiplexed, or have multiple identical copies.
How do I recover a control file?
When you are using a recovery catalog it is simpler to restore the control files. All you need to do is ensure that you connect to both your target database and the recovery catalog. Then issue startup nomount, and issue the restore controlfile command.
What is the purpose of a control file?
A control file is a small binary file that records the physical structure of the database and includes: The database name. Names and locations of associated datafiles and online redo log files. The timestamp of the database creation.
How do I fix a corrupted control file?
Recovering from Control File Corruption Using a Control File Copy
- With the instance shut down, use an operating system command to overwrite the bad control file with a good copy: % cp /u03/oracle/prod/control03.ctl /u02/oracle/prod/control02.ctl.
- Start SQL*Plus and open the database: SQL> STARTUP.
What are Oracle control files?
Every Oracle database has a control file. A control file is a small binary file that records the physical structure of the database and includes: The database name. Names and locations of associated datafiles and online redo log files. The timestamp of the database creation.
What is Oracle control file?
What happens if control file is lost?
If the control files are missing, then the database cannot be mounted, so at most, the database state is nomount. Any attempt to mount will fail because of the missing files.
What is a SCN in Oracle?
A system change number (SCN) is a logical, internal time stamp used by Oracle Database. SCNs order events that occur within the database, which is necessary to satisfy the ACID properties of a transaction.
Why is my ora-01207 file more recent than the controlfile?
ORA-01207: ORA-01207 file is more recent than controlfile – old controlfile Cause: The control file change sequence number in the datafile is greater than the number in the control file. This implies that the wrong control file is being used. Note that repeatedly causing this error can make it stop happening without correcting the real problem.
Why is my control file number greater than the datafile number?
Cause: The control file change sequence number in the datafile is greater than the number in the control file. This implies that the wrong control file is being used. Note that repeatedly causing this error can make it stop happening without correcting the real problem.
Why does the Control File Change sequence number keep changing?
This implies that the wrong control file is being used. Note that repeatedly causing this error can make it stop happening without correcting the real problem. Every attempt to open the database will advance the control file change sequence number until it is great enough.