How to correctly close the connections and resources of the MySQL connection pool and handle connection exceptions in a Shell script?

How to correctly close the connections and resources of the MySQL connection pool in a Shell script and handle connection exceptions?

MySQL is a popular relational database management system that is widely used in various applications. When using MySQL, it is a common practice to use a connection pool to manage database connections, which can improve the efficiency of database connection usage. When using the MySQL connection pool in a Shell script, you need to correctly close the connection and release resources, and also handle connection exceptions to ensure the stability and security of the program.

The following are several steps on how to correctly close the connections and resources of the MySQL connection pool and handle connection exceptions in a Shell script:

1. Get the connection: Use the MySQL command line tool or Other specific shell commands to obtain database connections. The connection parameters include host name, port number, user name, password, etc.
2. Execute SQL statements: Use the connection to execute the required SQL statements, including queries, inserts, updates and other operations. After execution, you can get the result set or the number of affected rows.
3. Close the connection: After using the connection in the Shell script, remember to close the connection to release resources. The connection can be closed using the QUIT command of the MySQL command line tool, or other specific Shell commands to close the connection.
4. Handling connection exceptions: It is very important to handle connection exceptions in Shell scripts. You can use try-catch statements to catch exceptions and handle them accordingly. When a connection exception occurs, logs can be recorded and error handling can be performed, such as retrying the connection, rolling back the transaction, etc.

The following is a sample Shell script that shows how to correctly close the connections and resources of the MySQL connection pool and handle connection exceptions in the Shell script:

#!/bin/bash

# 设置连接参数
HOST="localhost"
PORT="3306"
USER="root"
PASSWORD="password"
DATABASE="mydb"

# 获取连接
mysql -h $HOST -P $PORT -u $USER -p$PASSWORD $DATABASE <<EOF
    # 执行SQL语句
    try {
        # SQL操作
    } catch (Exception $e) {
        # 处理连接异常
        echo "连接异常：$e"
        # 记录日志
        echo "连接异常：$e" >> error.log
        # 错误处理
        # 重试连接或回滚事务等
    }
    # 关闭连接
    QUIT
EOF

# 处理其他业务逻辑

In this example, We used the MySQL command line tool to obtain the connection and perform the required SQL operations. In the try-catch block, we catch the connection exception and handle it accordingly. Finally, other operations can be performed within other business logic of the script.

Through the above steps, we can correctly close the connections and resources of the MySQL connection pool in the Shell script and handle the connection exception. This can ensure the normal use of the database connection and improve the stability and security of the program.

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