错误：连接丢失：服务器关闭连接节点js mysql答案

【问题标题】：Error: Connection lost: The server closed the connection node js mysql错误：连接丢失：服务器关闭连接节点js mysql
【发布时间】：2020-02-19 12:14:09
【问题描述】：

我收到此错误。一段时间后。我认为这个错误是因为 MySQL 处于空闲状态。有人建议我防止这个错误。

Error: Connection lost: The server closed the connection.
    at Protocol.end (/var/www/html/invoice/invoice2/node_modules/mysql/lib/protocol/Protocol.js:112:13)
    at Socket.<anonymous> (/var/www/html/invoice/invoice2/node_modules/mysql/lib/Connection.js:94:28)
    at Socket.<anonymous> (/var/www/html/invoice/invoice2/node_modules/mysql/lib/Connection.js:526:10)
    at Socket.emit (events.js:333:22)
    at endReadableNT (_stream_readable.js:1204:12)
    at processTicksAndRejections (internal/process/task_queues.js:84:21)
Emitted 'error' event on Connection instance at:
    at Connection._handleProtocolError (/var/www/html/invoice/invoice2/node_modules/mysql/lib/Connection.js:423:8)
    at Protocol.emit (events.js:321:20)
    at Protocol._delegateError (/var/www/html/invoice/invoice2/node_modules/mysql/lib/protocol/Protocol.js:398:10)
    at Protocol.end (/var/www/html/invoice/invoice2/node_modules/mysql/lib/protocol/Protocol.js:116:8)
    at Socket.<anonymous> (/var/www/html/invoice/invoice2/node_modules/mysql/lib/Connection.js:94:28)
    [... lines matching original stack trace ...]
    at processTicksAndRejections (internal/process/task_queues.js:84:21) {
  fatal: true,
  code: 'PROTOCOL_CONNECTION_LOST'
}

【问题讨论】：

标签： mysql node.js

【解决方案1】：

您好，当您使用与节点 js 服务器的正常连接连接 mysql 时，一段时间后您的 mysql 客户端将关闭所以你必须使用 pooling 机制连接到 mysql 服务器。

请通过这里您可以找到如何使用池连接连接 mysql (https://github.com/mysqljs/mysql#pooling-connections)

var mysql = require('mysql');
var pool  = mysql.createPool({
  connectionLimit : 10,
  host            : 'example.org',
  user            : 'bob',
  password        : 'secret',
  database        : 'my_db'
});

pool.query('SELECT 1 + 1 AS solution', function (error, results, fields) {
  if (error) throw error;
  console.log('The solution is: ', results[0].solution);
});

【讨论】：

【解决方案2】：

这是连接协议丢失的解决方案。这个解决方案解决了我

这里是数据库连接

const mysql = require('mysql');

const connection=mysql.createConnection({
    host:'localhost',
    user:'root',
    password:'******',
    database:'db_name'
});

connection.connect(function(error){
    if(!!error) console.log(error);
     else console.log('SQL Database Connected!');
});

module.exports = connection;`

只需使用 pm2 运行节点服务器，例如： pm2 start app.js

参考：Install the npm pm2 package

【讨论】：