NodeJS / express：开始运行一段时间后服务器被挂起

我用express和webpack做了我的服务，一开始它运行良好。 奇怪的是，一段时间后，服务（服务器）将挂起。 如屏幕截图所示，没有收到消息代码。 （服务器消息截图）而这种情况一再发生。

我的app.js

var express = require('express'); var path = require('path'); var favicon = require('serve-favicon'); var logger = require('morgan'); var cookieParser = require('cookie-parser'); var bodyParser = require('body-parser'); var index = require('./routes/index'); var users = require('./routes/users'); var app = express(); var mysql = require('mysql'); var generals = require('./routes/generals'); // view engine setup app.set('views', path.join(__dirname, 'views')); app.set('view engine', 'jade'); app.use(logger('dev')); app.use(bodyParser.json()); app.use(bodyParser.urlencoded({ extended: false })); app.use(cookieParser()); app.use('/generals', generals); app.use(express.static(path.join(__dirname, 'public'))); app.use('/', index); app.use('/users', users); // catch 404 and forward to error handler app.use(function(req, res, next) { var err = new Error('Not Found'); err.status = 404; next(err); }); // error handler app.use(function(err, req, res, next) { // set locals, only providing error in development res.locals.message = err.message; res.locals.error = req.app.get('env') === 'development' ? err : {}; // render the error page res.status(err.status || 500); res.render('error'); }); module.exports = app; 

这里是路由文件：generals.js

 var express = require('express'); var bodyParser = require('body-parser'); var router = express.Router(); var pool = require('./connections'); router.get('/dropDownValue/', function(req, res, next) { pool.getConnection(function(err, connection) { connection.query("select * from drop_down_value order by id desc", function(err, rows) { if (!err && rows.length > 0) { res.json(rows); } else { res.json([]); } }); }); }); 

和连接文件：

 var mysql = require('mysql'); var pool = mysql.createPool({ host: 'xxx', user: 'xxx', password: 'xxx', database: 'xxx' }); exports.getConnection = function (callback) { pool.getConnection(callback); }; 

Answer 1

当您使用pool.getConnection() ，一旦完成连接（即查询已完成），您需要再次将连接释放回池中：

 pool.getConnection(function(err, connection) { connection.query("select * from drop_down_value order by id desc", function(err, rows) { connection.release(); // <- this if (!err && rows.length > 0) { res.json(rows); } else { res.json([]); } }); }); 

否则，一旦执行了10个查询，池中就没有更多的连接可用，它将开始等待（无限期地）连接被释放，挂起请求。