Working with indexes

Like other databases, MongoDB needs to index data sets if we want queries on large sets to perform well.

In order to experience this firsthand, let's write a script which inserts 200,000 documents instead of just 20:

'use strict';

var MongoClient = require('mongodb').MongoClient;

MongoClient.connect(
  'mongodb://127.0.0.1:27017/accounting',
  function (err, connection) {
    var collection = connection.collection('customers');

    var doInsert = function (i) {
      if (i < 200000) {
        var value = Math.floor(Math.random() * 10);
        collection.insert(
          {'n': '#' + i, 'v': value},
          function (err, count) {
            doInsert(i + 1);
          });
      } else {
        connection.close();
      }
    };

    doInsert(0);

  });

Call this script insert.js and execute it running node...