如何加快猫鼬批量文档的更新

Question

我在MongoDB馆藏中大约有2000万个文档。 现在我想添加一个名为“分数”的字段，分数值是通过机器学习模型计算得出的。 现在，我的任务是遍历MongoDB中的每个文档，计算分数并更新文档。 但是问题在于更新过程需要很长时间才能完成。

这是我当前正在使用的代码。

const config = require('./config');
const mongoose = require('mongoose');
const audit = require("./lib/Audit")

const threads = 4;
let completed = 0;
let documents = 0;

mongoose.connect(config.db.uri, {useNewUrlParser: true, useCreateIndex: true});

console.log("Connected to mongodb!");
const Schema = require('./models/Schema.js');
const CliProgress = require('cli-progress');

const bar1 = new CliProgress.Bar({
  etaBuffer: 5000,
  format: '[{bar}] {percentage}% | ETA: {eta_formatted} | {value}/{total}'
}, CliProgress.Presets.shades_grey);


(async function (ref) {
  documents = await Schema.find({'score': null}).count();
  completed = 0;
  bar1.start(documents, completed);
  let corsor = Schema.find({'score': null}).cursor();

  corsor.eachAsync((doc) => {
    // console.log(update)
    doc.lastmod = Date.now();

    // Calculating The Score
    doc.score = audit(doc.toObject())
    doc.save();
    // Saving To Database
    completed ++;
    bar1.update(completed);
    return true;
  }, {parallel: threads })
})();

看看，让我知道如何加快流程？ 我已经尝试过通过增加线程的值来进行操作，但是它对操作速度几乎没有影响。

Answer 1

我有一个解决方案可以大大加快该过程！ 通过以这种方式使用批量操作，就我而言，此方法快约20倍。

const config = require('./config');
const mongoose = require('mongoose');
const Audit = require("./lib/Audit");
const ObjectId = require('mongodb').ObjectId;


let completed = 0;
let documents = 0;
let timeouts = null;


mongoose.connect(config.db.uri, {useNewUrlParser: true, useCreateIndex: true});

console.log("Connected to mongodb!");
console.log('\033[2J');

const Schema = require('./models/Schema.js');
const CliProgress = require('cli-progress');
const bar1 = new CliProgress.Bar({
  etaBuffer: 5000,
  format: '[{bar}] {percentage}% | ETA: {eta_formatted} | {value}/{total}'
}, CliProgress.Presets.shades_grey);


(async function (ref) {
  documents = await Schema.find({}).count();
  completed = 0;
  bar1.start(documents, completed);
  let corsor = Schema.find().lean().cursor();

  let bulk = Schema.collection.initializeOrderedBulkOp();

  corsor.on("data", (doc) => {

    // console.log(update)
    doc.lastmod = Date.now();

    doc.swarm.verified = true;
    if(doc.swarm.seeders || doc.swarm.leechers){
      doc.swarm.audit = Audit(doc);
    }

    bulk.find({_id: ObjectId(doc._id)}).updateOne({ $set: { "swarm": doc.swarm, lastmod: doc.lastmod }});

    completed ++;
    bar1.update(completed);
    return true;
  });

  corsor.on('end',() => {
    clearTimeout(timeouts);
    bulk.execute(()=> {
      console.log('\033[2J');
      console.log('Task Completed!');
      setTimeout(()=> {
        process.exit();
      }, 5000)
    });
  });

//  {parallel: 200}

  function start(){
    timeouts = setTimeout(() => {
      doTasks()
    }, 120000);
  }

  start();

  function doTasks() {
    corsor.pause();
    clearTimeout(timeouts);
    console.log('\033[2J');
    console.log('Updating Documents.....');
    console.log('Waiting For Complete.....');
    bulk.execute(()=> {
      // Done Writing Documents
      start()
      console.log('\033[2J');
      console.log('Resuming task........');
      // Start another Bulk Operation
      bulk = Schema.collection.initializeOrderedBulkOp();
      // Resume The cursor
      corsor.resume();
    });
  }
})();