有没有办法解决 node.js 中的 mysql 重新连接问题? [英] Is there a way to fix the mysql reconnection issue in node.js?

问题描述

您好，在调用 mysql 服务器时，如果连接由于长时间未使用而未打开/断开连接，那么当我尝试重新连接时，它会给我一个错误.我查过这个错误，但在我的情况下，这些回应似乎对我没有帮助.这是错误:在已经将握手入队后无法入队握手.这是导致此问题的代码:

Hello when making calls to the mysql server if the connection is not open/disconnected due to a long time of not using it then it will give me an error when I attempt to Re-Connect. I have looked this error up but the responses don't seem to help me in my situation. Here is the error: Cannot enqueue Handshake after already enqueuing a Handshake. Here is the code causing this:

var con = mysql.createConnection({
    host: "",
    user: "",
    password: "",
    database: ""
});

con.connect(function(err) {
    if (err) throw err;
    console.log("Connected!");
});

con.on('error', function(err) {
    console.log(err);
    console.log('MYSQL Disconnected');
})

if (con.state == 'disconnected') {
    con.connect(function(err) {
        if (err) throw err;
    });
}

下面有更多代码，但无关紧要，因为它会检查身份验证状态并进行查询

More code is below but is irrelevant due to it checking for authenticated state and querying

推荐答案

我发现 mysql.createConnection 和 mysql.createPool 之间的区别在于前者与MySQL(超时)，我需要重新启动节点服务器以重新建立连接.使用创建池，应用程序仅在需要时使用 mysql 连接，并且当 MySQL 超时时我不需要重新启动节点.

The difference I found between mysql.createConnection and mysql.createPool is when the former lost connection to MySQL (timeout), I need to restart the node server to re-establish connection. With create pool, the app only uses mysql connection when it's required and when MySQL timeout I don't need to restart the node.

试试这个，看看有没有好处:

Try this and see if there's any good:

dbConnectionInfo = {
  host: "",
  user: "",
  password: "",
  database: ""
};

var con = mysql.createPool(
  dbConnectionInfo
);

con.on('connection', function (connection) {
  console.log('DB Connection established');

  connection.on('error', function (err) {
    console.error(new Date(), 'MySQL error', err.code);
  });
  connection.on('close', function (err) {
    console.error(new Date(), 'MySQL close', err);
  });
});

这个方法是我从一个帖子中找到的，但我不记得是哪个，因为我见过很多 mysl.createPool.您可以在此处找到更多方法

This method I found from a post but I can't remember which one because there are a lot of mysl.createPool I've seen. You may find more methods here

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