mysql close connection

MySQL is a mainstream relational database management system. Many applications use MySQL to store and manage data. The MySQL connection can be maintained until the application is closed or closed manually. However, in some cases, the MySQL connection needs to be closed in time to avoid resource waste and security risks.

1. Close the connection manually

Manually closing the MySQL connection is the most basic method. You can use the following code to manually close the connection in PHP:

mysqli_close($conn);

Where, $conn is the connection object, use mysqli_connect to connect to the database and return $conn. After the above code is executed, the connection object will be destroyed and the connection will be closed.

2. Close the connection pool

If you use a connection pool to manage MySQL connections, you can close the connection by closing the connection pool. A connection pool is a set of reusable database connections that can effectively reduce the number of times an application connects and disconnects to the database. However, if the connection pool is not closed, the connection will remain open, which may occupy a lot of system resources.

The following is the code to close the connection pool in Java:

DataSource dataSource = // 创建数据源
Connection connection = dataSource.getConnection(); // 获取连接对象
// 执行数据操作
connection.close(); // 关闭连接对象
dataSource.close(); // 关闭连接池

In the above code, the data source is created by the developer himself, and the connection pool can be closed by calling the close() method. At this time, all connections in the connection pool will be released and the connections will be closed.

3. Timeout Control

MySQL also provides a timeout control option to close connections that have not been used for a long time. This option is called wait_timeout. In the MySQL configuration, wait_timeout is set to 8 hours by default. If a connection does not perform any operations for 8 hours, it will be automatically closed.

If you need to change the value of wait_timeout, you can execute the following command in the MySQL command line:

SET SESSION wait_timeout = xxx;

Where, xxx is the timeout in seconds. For example, to set wait_timeout to 5 minutes (300 seconds), you can execute the following command:

SET SESSION wait_timeout = 300;

After the above command is executed, MySQL will automatically wait for 300 seconds if the current connection does not perform any operations. Close the connection.

In development, we should use appropriate methods to close the MySQL connection. Closing connections promptly can effectively reduce resource waste and security risks.

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