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node.js - Nodejs Mongodb 发现性能问题

问题描述

我最近刚接触 mongodb，到那时我遇到了很多问题。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，问题是它需要很长时间才能执行，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连接不是办法，我只是用这个函数来测试。

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");
  });
  }

我尝试获得所有承诺，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，这对于如此小的查询来说非常慢

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

我做错了什么？是承诺所有功能需要很长时间才能执行还是我的 Mongodb 查询有问题？

标签： node.jsmongodbpromisemongodb-query

解决方案

问题是您每次都创建一个到 mongo 的新连接。

解决方案是创建一个连接并保持它处于活动状态并在不再需要时关闭它（当应用程序停止时）。

此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");
    });
};

还要记住在您搜索的那些字段上在 mongo 上创建索引（例如gameID在这种情况下）。通过这种管理，您可以更快地访问数据。

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