The contents are of my own testing and deployments. Not guaranteed that these might work in your environment. Please test before usage.
Summary: in this tutorial, you will learn What is Controlfile in oracle database,
Control File:
1) The Control file is a file with a .ctl extension that is physically stored on the operating system that is a must for an Oracle database.
2)This file also acts as the brain for our Oracle database. When the Oracle database starts, it reads the parameter file called SPFILE or PFILE and learns the location of the Control file.
3)Because the Control file is the brain of our database, the database needs to find this file to work. If it cannot find the Control File, the Oracle database will not start and will give an error.
4)That's why, the control file is stored in 2 copies in the production databases. Oracle’s recommended configuration is that we store 3 copies on separate disks. We said the control file is very important. So why is important, what information is in the control file.
Including:-
--Database name and Identifier
--Time stamp of database creation
--Tablespace names
--Names and Locations of datafiles and Online redo Logfiles.
--Current Online Redo Logfiles sequence number(LSN)
-- Checkpoint Information
--Begin and end of Undo segments
--Redo Log Archive information
--Backup Information.
Show control file:
SQL> show parameter control
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
control_file_record_keep_time integer 7
control_files string /home/oracle/service/oradata/control/control01.ctl, /home/oracle/service/oradata/control/control02.ctl
control_management_pack_access string DIAGNOSTIC+TUNING
SQL> select name from v$controlfile;
NAME
-----------------------------------------------------------
/home/oracle/service/oradata/control/control01.ctl
/home/oracle/service/oradata/control/control02.ctl
Note: Don't try to open or cat that control file!
Thanks for your time!!
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