Different modes to shutdown Oracle Database

11:23 Posted by Unknown

DATABASE SHUTDOWN IN DIFFERENT MODES

When shutting down an instance, perform these steps, which are reverse from those you just saw when opening a database:

Close the database, including the data files and redo logs, so that it is no longer usable for normal tasks.
Unmount the database from the instance so that only the instance memory structures and background tasks are left running without a database associated with them.
Shut down the instance to close the control files.

In order to shut down a database, four different approaches can be used: Shutdown Normal, Immediate, Transactional, and Abort.

Normal is, in a sense, the “perfect” way to shut down, since this approach will wait for all users to disconnect from the database and all transactions to complete before the shutdown occurs. Once this command has been issued, new users are not allowed into the system. This can be impractical in cases where users remain on the system for long periods of time.

> shutdown normal;

Immediate is a practical shutdown approach that also leaves the database in a consistent state. When the database is put through a “shutdown immediate,” all current transactions are rolled back and users are disconnected. No new transactions are allowed into the system. This will be relatively quick if the rollback operations are small, and is an excellent way to shut down the database before performing a database backup.

> shutdown immediate;

transactional shutdown is similar to the immediate variety except that running transactions are allowed to complete. So, once transactions have been committed, the user running it is disconnected. This is useful in cases where you do not want to shutdown until currently running transactions have finished or in cases where it will be quicker to complete existing transactions than it will be to roll them back.

> shutdown transactional

Abort is the least graceful shutdown option of the four. When this is used, all transactions are ended immediately without waiting for a rollback or commit and all users are instantly disconnected while the database is brought down. Use this only if you are experiencing problems shutting down the database using one of the three options described previously or in cases where you need to shutdown the database immediately. The database needs to go through recovery procedures the next time it is restarted. After a shutdown abort has been performed, you should try to immediately start up the database so that you can then perform a shutdown (normal, immediate, or transactional) to bring the database down in the proper manner.

> shutdown abort;

Tags: Oracle Database, Shutdown

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