How to implement automatic reconnection of MySQL?

MySQL is an open source relational database management system that is widely used in web development and data storage. However, when performing database operations, sometimes the MySQL connection is disconnected, which may be caused by unstable network, abnormal database server, etc. When a connection is disconnected, it needs to be reconnected in time to ensure the normal operation of the system. So, how to achieve automatic reconnection of MySQL connections?

First of all, we need to understand the reason for MySQL connection disconnection and the corresponding error code. In MySQL, once the connection is disconnected, an error code is sent to the client, usually 2006 or 2013. When receiving these error codes, we can determine whether the connection is disconnected and proceed with subsequent processing.

Next, we can add some logic to the application code to detect the connection status and reconnect. Here is a sample code:

import pymysql
import time

def connect_mysql():
    while True:
        try:
            connection = pymysql.connect(host='localhost', user='root', password='password', db='database')
            if connection.open:
                print("成功连接到MySQL数据库")
                return connection
            else:
                print("连接失败，正在重新连接...")
        except pymysql.Error as e:
            if e.args[0] == 2006 or e.args[0] == 2013:
                print("连接断开，正在重新连接...")
            else:
                print("发生其他错误，无法重新连接")
                break
        time.sleep(5)

In the above code, we first try to establish a MySQL connection. If the connection is successful, we can perform database operations normally. If the connection fails, we will check the error code. If the error code is 2006 or 2013, it means the connection is disconnected. We will output the corresponding prompt information and reconnect. If the error code is any other value, it means that another error has occurred and we will stop the connection operation.

In order to increase the stability of reconnection, we can use an infinite loop to continuously try to reconnect. Use the time.sleep() function to add a delay before each reconnection to avoid stress caused by frequent connections to the database server.

Finally, call the connect_mysql() function in the application to establish a database connection. The advantage of this is that when the MySQL connection is disconnected, the system will automatically re-establish the connection and continue database operations.

In summary, when the MySQL connection is disconnected, we can determine the connection status by detecting the error code, and use appropriate code logic to automatically reconnect. In this way, we can ensure the stability of the MySQL connection and ensure the normal operation of the system.

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