我试图在while循环中执行一堆非常大的SELECT语句（每个语句都需要几分钟才能完成执行）。
var con = mysql.createConnection(
{
host: "host_name",
user: "user_name",
password: "password",
database: "database_name"
});
con.connect();
while(arg1 < arg2)
{
var query = SELECT * FROM table WHERE value=arg1;
con.query(query, function (err, result)
{
//Rest of code
});
arg = arg + 1;
}
con.end();
起初，它正在工作，但很快，经过一段时间后，连接似乎就丢失了。
Connection lost: The server closed the connection.
at Protocol.end (C:\Users\X\node_modules\mysql\lib\protocol\Protocol.js:109:13)
at Socket.<anonymous> (C:\Users\X\node_modules\mysql\lib\Connection.js:109:28)
at emitNone (events.js:110:20)
at Socket.emit (events.js:207:7)
at endReadableNT (_stream_readable.js:1047:12)
at _combinedTickCallback (internal/process/next_tick.js:102:11)
at process._tickCallback (internal/process/next_tick.js:161:9)
在阅读Stack上的一些类似问题之后，由于Github上的Mysql页面，我明白了原因：
由于网络问题，服务器计时，服务器重启或崩溃，您可能会丢失与MySQL服务器的连接。
因此，为了处理可能的断开连接，我尝试使用此功能，遵循上一篇文章的工作：
function handleDisconnect() {
connection = mysql.createConnection(db_config);
connection.connect(function(err) {
if(err) {
console.log('error when connecting to db:', err);
setTimeout(handleDisconnect, 2000);
}
});
connection.on('error', function(err) {
console.log('db error', err);
if(err.code === 'PROTOCOL_CONNECTION_LOST') {
handleDisconnect();
}
else
{
throw err;
}
});
}
在以下代码中：
while(arg1 < arg2)
{
handleDisconnect();
var query = SELECT * FROM table WHERE value=arg1;
connection.query(query, function (err, result)
{
//Rest of code
});
arg = arg + 1;
}
但我仍然收到以下错误消息：
error when connecting to db: { Error: Connection lost: The server closed the connection.
at Protocol.end (C:\Users\X\node_modules\mysql\lib\protocol\Protocol.js:109:13)
at Socket.<anonymous> (C:\Users\X\node_modules\mysql\lib\Connection.js:109:28)
at emitNone (events.js:110:20)
at Socket.emit (events.js:207:7)
at endReadableNT (_stream_readable.js:1047:12)
at _combinedTickCallback (internal/process/next_tick.js:102:11)
at process._tickCallback (internal/process/next_tick.js:161:9)
--------------------
at Protocol._enqueue (C:\Users\X\node_modules\mysql\lib\protocol\Protocol.js:141:48)
at Protocol.handshake (C:\Users\X\node_modules\mysql\lib\protocol\Protocol.js:52:41)
at Connection.connect (C:\Users\X\node_modules\mysql\lib\Connection.js:130:18)
at handleDisconnect (C:\Users\X\connection.js:182:13)
at Object.<anonymous> (C:\Users\X\connection.js:105:2)
at Module._compile (module.js:569:30)
at Object.Module._extensions..js (module.js:580:10)
at Module.load (module.js:503:32)
at tryModuleLoad (module.js:466:12)
at Function.Module._load (module.js:458:3) fatal: true, code: 'PROTOCOL_CONNECTION_LOST' }
C:\Users\X\connection.js:213
if (err) throw err;
^
Error: Connection lost: The server closed the connection.
at Protocol.end (C:\Users\X\node_modules\mysql\lib\protocol\Protocol.js:109:13)
at Socket.<anonymous> (C:\Users\X\node_modules\mysql\lib\Connection.js:109:28)
at emitNone (events.js:110:20)
at Socket.emit (events.js:207:7)
at endReadableNT (_stream_readable.js:1047:12)
at _combinedTickCallback (internal/process/next_tick.js:102:11)
at process._tickCallback (internal/process/next_tick.js:161:9)
--------------------
at Protocol._enqueue (C:\Users\X\node_modules\mysql\lib\protocol\Protocol.js:141:48)
at Protocol.handshake (C:\Users\X\node_modules\mysql\lib\protocol\Protocol.js:52:41)
at Connection.connect (C:\Users\X\node_modules\mysql\lib\Connection.js:130:18)
at handleDisconnect (C:\Users\X\connection.js:182:13)
at Object.<anonymous> (C:\Users\X\connection.js:105:2)
at Module._compile (module.js:569:30)
at Object.Module._extensions..js (module.js:580:10)
at Module.load (module.js:503:32)
at tryModuleLoad (module.js:466:12)
at Function.Module._load (module.js:458:3)
有什么东西我没有得到或有什么我应该知道成功管理断开连接？我仍然遇到Node JS的问题，理解如何处理同步和异步函数的概念，也许我的问题来自这里。