How to shut down oracle

Oracle database is a high-performance, reliable, and secure relational database management system that is widely used in enterprise-level applications and large data centers. However, in some cases, it is necessary to temporarily shut down the Oracle database, such as for backup, upgrade, repair, etc. So, how to shut down the Oracle database correctly? This article will introduce how to shut down the Oracle database and precautions.

1. Close the Oracle database normally

1. Close all connections

Before closing the Oracle database, you need to close all database connections. If there is a connection that is not processed, there is a risk of data corruption or even data loss. You can use the following command to view all connections:

SQL> select username, machine, osuser, program
     from v$session;

Where:

• username: connected username
• machine: connected machine name
• osuser: The connected operating system user name
• program: The connected program name

Use the following command to forcefully disconnect all connections:

SQL> alter system disconnect session '用户名,SESSIONID,@机器名' immediate;

Note that the above command will Forcibly disconnecting may cause the user's ongoing operations to be lost, so please use it with caution!

2. Close the listener

Before closing the Oracle database, you also need to close the listener. Without closing the listener, the database cannot be started again. You can use the following command to shut down the listener:

$ lsnrctl stop

3. Close the database instance

Finally, you can use the following command to shut down the database instance:

SQL> shutdown immediate;

Note that this The database instance will be shut down immediately. However, if there are unprocessed transactions, it will wait until the transactions are processed before shutting down.

2. Forcefully close the Oracle database

If the database cannot be shut down normally, you can try to use the following command to forcefully shut down the database:

SQL> shutdown abort;

This will immediately terminate all running processes. It may cause data corruption or data loss risk and is not recommended for use under normal circumstances.

3. Precautions for closing the Oracle database

1. Back up first

Before closing the Oracle database, you should back up the database first. This ensures that data can be recovered if something unexpected happens after a shutdown. For backup, you can use Oracle's own backup tool or a third-party backup tool.

2. Close the application first

Before closing the Oracle database, you should close the applications related to it to prevent misoperations from causing system crashes. In addition, closing the application can avoid disconnection while the user is working on it.

3. Close the listener first

Before closing the Oracle database, you should close the listener first. Without closing the listener, the database cannot be started again.

4. Close the connection first

Before closing the Oracle database, all connections should be closed first. If there is a connection that is not processed, there is a risk of data corruption or even data loss.

5. Attention to permission issues

Before closing the Oracle database, you need to log in to the Oracle database with administrator privileges. In addition, you need to ensure that you have sufficient permissions when executing the shutdown command.

6. Pay attention to the shutdown sequence

When closing the Oracle database, you need to pay attention to the shutdown sequence. You should first close the application, listener and connection, and then close the database instance. This ensures a graceful shutdown of the database, avoiding the risk of data loss and corruption.

Summary: Closing the Oracle database is a very important operation and needs to be taken seriously. Before closing the Oracle database, you need to back up the data, close the application, close the listener and connection, and log in to the Oracle database with administrator rights. The shutdown sequence should be: shut down the application, listeners, and connections first, then shut down the database instance. If the database cannot be closed normally, you can try to force the database to close, but this will bring potential risks of data corruption or data loss, so use it with caution.

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