Node.js Nodejs代码崩溃Mongodb服务器

我在mongodb的一个收藏中有大约30万个文档，这些文档都放在AWS中。当我查询这个特定的路由（thing2）时，似乎mongo处理的太多了，所以mongod服务崩溃了。我已经给我的代码增加了一个限制，但它仍然不起作用。理想情况下，我希望能够搜索特定的关键字，但这部分已经被注释掉了

var express = require('express')
var app = express()

app.get('/', function (req, res) {
    res.send('Hello World!')
});

app.get('/thing2', function(req, res) {

    var username = req.query.username
    var keyword = req.query.keyword

    var MongoClient = require('mongodb').MongoClient,
        assert = require('assert');
    var url = 'mongodb://localhost:27017/my_db';

    MongoClient.connect(url, function(err, db) {
        if (err) throw err;

        var collection = db.collection('my_collection');
        / * collection.find({ $and: [ 
          * {"text" : {$regex : ".*"+keyword+".*"}}, 
          *  {"username" : username}
          *  ] }).limit(5).toArray(function(err, docs) {
          */

        collection.find({"user.screen_name" : username}).limit(1).toArray(function(err, docs) {
            console.log("\n" + new Date().toLocaleString() + " " + username);

            if (!err) {
                console.log(docs.length)
            } else {
                console.log(err)
            }

            res.send(docs)
        });
    });
});

app.listen(80, function () {
    console.log('Listening on port 80!')
});

我在控制台中看到的错误是：

{ [MongoError: connection 0 to localhost:27017 closed]
  name: 'MongoError',
  message: 'connection 0 to localhost:27017 closed' }

编辑：mongo日志

2017-04-19T03:59:03.458+0000 I CONTROL  [initandlisten] 
2017-04-19T03:59:03.458+0000 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.
2017-04-19T03:59:03.458+0000 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2017-04-19T03:59:03.458+0000 I CONTROL  [initandlisten] 
2017-04-19T03:59:03.458+0000 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2017-04-19T03:59:03.458+0000 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2017-04-19T03:59:03.458+0000 I CONTROL  [initandlisten] 
2017-04-19T03:59:03.471+0000 I FTDC     [initandlisten] Initializing full-time diagnostic data capture with directory '/var/lib/mongodb/diagnostic.data'
2017-04-19T03:59:03.471+0000 I NETWORK  [initandlisten] waiting for connections on port 27017
2017-04-19T03:59:03.471+0000 I NETWORK  [HostnameCanonicalizationWorker] Starting hostname canonicalization worker
2017-04-19T03:59:04.003+0000 I FTDC     [ftdc] Unclean full-time diagnostic data capture shutdown detected, found interim file, some metrics may have been lost. OK
2017-04-19T03:59:23.504+0000 I COMMAND  [ftdc] serverStatus was very slow: { after basic: 40, after asserts: 110, after connections: 130, after extra_info: 160, after globalLock: 310, after locks: 540, after network: 630, after opcounters: 760, after opcountersRepl: 870, after storageEngine: 1120, after tcmalloc: 1540, after wiredTiger: 2690, at end: 3370 }

---

问题是你连接得太频繁了。我会使用mongoose重新编写代码：

var express = require('express')
var app = express()
var mongoose   = require('mongoose');
mongoose.connect('mongodb://localhost/my_db')
var collection = require('user');

app.get('/', function (req, res) {
    res.send('Hello World!')
});

app.get('/thing2', function(req, res) {

    var username = req.query.username
    var keyword = req.query.keyword

    collection.find({"user.screen_name" : username}).limit(1).toArray(function(err, docs) {
            console.log("\n" + new Date().toLocaleString() + " " + username);

            if (!err) {
                console.log(docs.length)
            } else {
                console.log(err)
            }
            res.send(docs)
    });
});

app.listen(80, function () {
    console.log('Listening on port 80!')
});

您可以像这样对mongoose模式建模（文件名为：“user.js”）：

尽量使其工作最小，然后增加与您真正的模型。

---

希望我的回答是有帮助的

您不需要（不应该）在有请求时一直连接。您可以在开始时连接一次，然后在整个应用程序中继续使用此连接。@israel.zing那么我如何修复此问题？当服务崩溃时，mongo日志会说什么？你是在玩nano吗？Mongo很结实normally@Matt如何找到mongo日志？我在t2.micro（免费层）

sudoless/var/log/mongodb/mongod.log

var mongoose     = require('mongoose');
var Schema       = mongoose.Schema;

var UserSchema   = new Schema({
    name: String,
    userId : Number
});
module.exports = mongoose.model('User', UserSchema);