About Oracle Database Shutdown
I have talked about Oracle Database startup before. Let's talk about Oracle Database shutdown today.
I. Three Phases of database ShutdownThe Oracle Database startup process involves three steps: NOMOUNT-> MOUNT-> OPEN. The database SHUTDOWN actually involves three steps:
CLOSE-> DISMOUNT-> SHUTDOWN. SQL> SHUTDOWN; Database closed.
2. Four options for database Shutdown
In the production environment, this method is rarely used to close databases with a large number of user connections.This is the most common way to close a database.When you use this command, the transaction being processed by Oracle is immediately interrupted, and uncommitted transactions are rolled back. The system does not wait for the user connected to the database to exit, force disconnect all connected users. Then run the Check Point to write all the changed data back to the data file and close the database. You can use this method to shut down the database. You do not need to restore the database instance the next time you start the database. This is a safe way to shut down the database. However, if the database system is busy and a large number of transactions are being executed, it may take a lot of time to use this option to close the database. The least recommended database shutdown MethodWith this option, the database will immediately terminate all user connections, interrupt all transactions, and shut down the database. In this way, the database will not be rolled back and the database will not execute checkpoints, so the next time you start the city, the database must restore the instance. It may take a lot of time to recover the instance, and it may take a long time to start the database.
The ABORT method is similar to the database server's sudden power failure., May cause inconsistency, so do not close the database easily unless you have. Refer:About starting the Remote DBA team of Oracle Database-Oracle Database Startup & Shutdown Process
