What does Oracle control file contains?

What does Oracle control file contains?

Every Oracle Database has a control file, which is a small binary file that records the physical structure of the database. The control file includes: The database name. Names and locations of associated datafiles and redo log files.

What is the use of control file in Oracle?

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.

How do I manually create a control file in Oracle 11g?

Complete the following steps to create a new control file.

  1. Make a list of all datafiles and redo log files of the database.
  2. Shut down the database.
  3. Back up all datafiles and redo log files of the database.
  4. Start up a new instance, but do not mount or open the database: STARTUP NOMOUNT.

In which mode is control file generated in Oracle DB?

If you omit both the ARCHIVELOG clause and NOARCHIVELOG clause, then Oracle Database chooses noarchivelog mode by default. After creating the control file, you can change between archivelog mode and noarchivelog mode with the ALTER DATABASE statement.

What is the importance of a control file?

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.

Where are Oracle control files located?

Locating Control Files

  1. The preconfigured database contains two control files located in the ORACLE_BASE\oradata \DB_NAME directory.
  2. The preconfigured database contains two control files located in the ORACLE_BASE\oradata \DB_NAME directory.
  3. A control file is an administrative file.

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 difference between Pfile and Spfile in Oracle?

The SPFILE is different from the PFILE in that it can not be directly edited. This is because it has a header and footer that contain binary values. Since you can not change a SPFILE directly, Oracle allows you to manage the SPFILE via the ALTER SYSTEM command.

What is control file used for and why its important?

How do I create a control file in Oracle?

1 Answer

  1. Shut down the database.
  2. Copy an existing control file to a new location, using operating system commands.
  3. Edit the CONTROL_FILES parameter in the database initialization parameter file to add the new control file name, or to change the existing control file name.
  4. Restart the database.

What is a CTL file?

ActiveX control created with Visual Basic development software; saved in a plain text format that contains the source code and properties for a Visual Basic UserControl. Binary control data is saved in a corresponding .

How do I recreate control files?

SQL> alter database backup controlfile to trace; A trace file will be generated in the user_dump_destination directory. After navigating to the directory locate the latest trace file by date/time by issuing “ls -ltr” command. Modify the trace file and use it as a script to create the control.

Which file is editable Pfile or Spfile?

SPFILE is a binary file that contains the same information as the old PFILE. SPFILE permits dynamic changes without requiring you to restart that instance. By default, if you do not specify PFILE in your STARTUP command, Oracle will use server parameter file (SPFILE).

What is parameter file in Oracle 11g?

A server parameter file (also referred to as SPFILE) is server-side initialization parameter file. It is a repository for initialization parameters and is maintained on the machine where the Oracle server executes.

What is PGA and SGA?

SGA (System Global Area) PGA (Program or Process Global Area) It is a memory area assigned at the time of an instance start up. It is a memory area that conserve the information regarding the user session.

To create a control file, you must have the SYSDBA system privilege. The database must not be mounted by any instance. After successfully creating the control file, Oracle mounts the database in the mode specified by the CLUSTER_DATABASE parameter. The DBA must then perform media recovery before opening the database.

How many control files should an Oracle Database have?

Every Oracle Database should have at least two control files, each stored on a different physical disk. If a control file is damaged due to a disk failure, the associated instance must be shut down.

What’s new in Oracle Database 11g?

In Oracle Database 11g, the new Data Recovery Advisor makes this operation much easier. The advisor comes in two flavors: command line mode and as a screen in Oracle Enterprise Manager Database Control. Each flavor has its advantages for a given specific situation.

What are the risks of using the create controlfile statement?

The CREATE CONTROLFILE statement can potentially damage specified data files and redo log files. Omitting a filename can cause loss of the data in that file, or loss of access to the entire database. Use caution when issuing this statement and be sure to follow the instructions in “Steps for Creating New Control Files”.