Nodejs Mongodb发现性能问题

Question

我最近刚刚着手开发mongodb，到那时我已经遇到了很多问题。我正在创建一个纸牌游戏，所以我认为mongodb将是最好的选择。

现在我正试图找到我所有的牌组、手牌和桌牌，问题是执行起来需要很长时间，即使收集量很小。

例如

{"_id":"5bd3323b1431aa01eed604a8","userID":1,"handData":[{"id":"MLTOG","suit":"Spades","value":5,"face":"5","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"3ZgGQ","suit":"Spades","value":3,"face":"3","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"zdgyN","suit":"Clubs","value":2,"face":"2","userHide":false,"globalHide":false,"hasSuperPower":true},{"id":"oy4CS","suit":"Spades","value":4,"face":"4","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"PgTxA","suit":"Diamonds","value":3,"face":"3","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"zlx6Y","suit":"Diamonds","value":4,"face":"4","userHide":false,"globalHide":false,"hasSuperPower":false}]}
{"_id":"5bd3315f11716c01d3a5a4a4","gameID":"aasd12","deckData":[{"id":"rPd2D","suit":"Diamonds","value":7,"face":"7","userHide":false,"globalHide":false,"hasSuperPower":true},{"id":"ZslMO","suit":"Hearts","value":14,"face":"Ace","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"vJ4j2","suit":"Hearts","value":13,"face":"King","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"sQWuO","suit":"Clubs","value":12,"face":"Queen","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"SV6wb","suit":"Clubs","value":4,"face":"4","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"XGut7","suit":"Hearts","value":4,"face":"4","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"jmiM8","suit":"Hearts","value":3,"face":"3","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"BqQgl","suit":"Hearts","value":7,"face":"7","userHide":false,"globalHide":false,"hasSuperPower":true},{"id":"1sDky","suit":"Hearts","value":6,"face":"6","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"PWTot","suit":"Spades","value":12,"face":"Queen","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"ctBqJ","suit":"Spades","value":10,"face":"10","userHide":false,"globalHide":false,"hasSuperPower":true},{"id":"g7MX1","suit":"Clubs","value":7,"face":"7","userHide":false,"globalHide":false,"hasSuperPower":true},{"id":"voGO8","suit":"Hearts","value":5,"face":"5","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"SeOwQ","suit":"Spades","value":14,"face":"Ace","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"67eKt","suit":"Clubs","value":11,"face":"Jack","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"rBfas","suit":"Spades","value":13,"face":"King","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"xD5X6","suit":"Clubs","value":14,"face":"Ace","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"91yRB","suit":"Diamonds","value":11,"face":"Jack","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"TMbbQ","suit":"Spades","value":7,"face":"7","userHide":false,"globalHide":false,"hasSuperPower":true},{"id":"6NQvl","suit":"Diamonds","value":5,"face":"5","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"0pMrB","suit":"Clubs","value":10,"face":"10","userHide":false,"globalHide":false,"hasSuperPower":true},{"id":"zIMFm","suit":"Hearts","value":12,"face":"Queen","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"KeQNt","suit":"Hearts","value":8,"face":"8","userHide":false,"globalHide":false,"hasSuperPower":true},{"id":"KSxvM","suit":"Clubs","value":8,"face":"8","userHide":false,"globalHide":false,"hasSuperPower":true},{"id":"MaNEM","suit":"Clubs","value":5,"face":"5","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"jU2h3","suit":"Hearts","value":10,"face":"10","userHide":false,"globalHide":false,"hasSuperPower":true},{"id":"VqKOQ","suit":"Diamonds","value":9,"face":"9","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"S0dz2","suit":"Spades","value":2,"face":"2","userHide":false,"globalHide":false,"hasSuperPower":true},{"id":"ehIbj","suit":"Spades","value":6,"face":"6","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"VsDTD","suit":"Diamonds","value":13,"face":"King","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"tmzY9","suit":"Clubs","value":3,"face":"3","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"eSQ8n","suit":"Hearts","value":2,"face":"2","userHide":false,"globalHide":false,"hasSuperPower":true},{"id":"y3fEo","suit":"Clubs","value":9,"face":"9","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"m5EBi","suit":"Diamonds","value":14,"face":"Ace","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"4IFqQ","suit":"Diamonds","value":10,"face":"10","userHide":false,"globalHide":false,"hasSuperPower":true},{"id":"KlGhF","suit":"Spades","value":8,"face":"8","userHide":false,"globalHide":false,"hasSuperPower":true},{"id":"wsLfO","suit":"Diamonds","value":12,"face":"Queen","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"9O44l","suit":"Hearts","value":11,"face":"Jack","userHide":false,"globalHide":false,"hasSuperPower":false},{"id":"H0r9u","suit":"Diamonds","value":6,"face":"6","userHide":false,"globalHide":false,"hasSuperPower":false}]}

fetch函数是这样的，当然mongoClient连接是不可行的，但我只是使用这个函数进行测试。

const getDeckCards =  (gameid) =>{
return new Promise ((resolve,reject) => {
console.time("deck");
MongoClient.connect(url, { useNewUrlParser: true }, function (err, client) {
const db = client.db(dbName);
const collection = db.collection("deck");
resolve(collection.find({ gameID: gameid }).project({ _id: 0, gameID: 0 }).toArray());
});
console.timeEnd("deck");
});
}
const getHandCards =  (userid) =>{
return new Promise ((resolve,reject) => {
console.time("hand");
MongoClient.connect(url, { useNewUrlParser: true }, function (err, client) {
const db = client.db(dbName);
const collection = db.collection("hand");
resolve(collection.find({ userID: userid }).project({ _id: 0, userID: 0 }).toArray());
});
console.timeEnd("hand");
});
}
const getTableCards =  (gameid) =>{
return new Promise ((resolve,reject) => {
console.time("table");
MongoClient.connect(url, { useNewUrlParser: true }, function (err, client) {
const db = client.db(dbName);
const collection = db.collection("table");
resolve(collection.find({ gameID: gameid }).project({ _id: 0, gameID: 0 }).toArray());
});
console.timeEnd("table");
});
}

我试图获得所有的承诺，然后将它们作为数组返回。

const initGame = (async() => {
console.time("init");
let [deck,hand,table] = await Promise.all([
getDeckCards("aasd12"),
getHandCards(1),
getTableCards("aasd12")
])
console.timeEnd("init");
return [deck[0],hand[0],table[0]];
});

它表明deck，hand，table函数非常快，这是我希望得到的结果，但整个结果需要1秒，对于这样的小查询来说，这是非常慢的

deck: 12.235ms
hand: 1.977ms
table: 0.534ms
init: 1058.646ms

我做错了什么？是promise all函数需要很长时间才能执行，还是我的Mongodb查询有问题？

Answer 1

问题是每次都要创建一个到mongo的新连接。

解决方案是创建一个连接并保持其活动状态，然后在不再需要时(应用程序停止时(关闭它。

这个示例代码肯定会对您的性能产生很好的影响：

class GameManager {
constructor() {
this.mongoClient = null;
}
async connect(dbName) {
this.mongoClient = await MongoClient.connect(url, { useNewUrlParser: true });
this.db = this.mongoClient.db(dbName);
}
getDeckCards(gameId) {
if (!this.mongoClient) {
return Promise.reject();
}
return this.db.collection("deck")
.find({ gameID: gameId })
.project({ _id: 0, gameID: 0 })
.toArray();
}
}
const initGame = () => {
console.time("init");
const gameManager = new GameManager();
return gameManager.connect(dbName)
.then(() => {
return Promise.all([
getDeckCards("aasd12"),
getHandCards(1),
getTableCards("aasd12")
])
})
.then(() => {
console.timeEnd("init");
});
};

还记得在mongo上对您搜索的字段(例如本例中的gameID(创建INDEX。有了这种管理，您可以更快地访问数据。