mongoose: 10x slowdown on Windows when upgrading from Mongoose 4 to 5.

@NewEraCracker is spot on, good call. The reason for this slowdown is that, starting in mongodb driver 3.0.0, the mongodb driver tries to connect using ipv6 first, and falls back to ipv4 if that fails unless you set the family option or use an ipv4 address like 127.0.0.1. The 1 second delay is because the driver’s trying to connect to localhost using ipv6, but presumably either your mongodb server isn’t configured to accept ipv6 connections or localhost isn’t configured to point to an ipv6 address. Below are the relevant links

https://github.com/mongodb-js/mongodb-core/commit/107bae5083d40b8521b5796469ddbc3ea2063c7a https://jira.mongodb.org/projects/NODE/issues/NODE-1222?filter=allissues https://github.com/mongodb-js/mongodb-core/pull/260

As a workaround, do this:

const mongoose = require('mongoose');

const run = async () => {
  let beforeConnection = Date.now();
  await mongoose.connect('mongodb://localhost/somedb', { family: 4 });
  let afterConnection = Date.now();

  console.log(`Time to connect is: ${(afterConnection - beforeConnection) / 1000}s`);
};

run().catch(console.error);

We’ll add documentation around this option

Yeah I can confirm that switching to 127.0.0.1 from localhost speeds up initial connection from 1000ms to 30ms on windows. Currently digging in to why this is the case.

Already switched to 127.0.0.1 in the connection string, and the tests run much faster now.

Thank you!

Are you connecting by name or IP?

On the example you posted, you documented localhost, if you replace that with 127.0.0.1 does it workaround the issue?

Regards, NewEraCracker

a bug? label would be great, needs repro script on an issue that’s been abandoned for a while may give the wrong idea to the developers.

Perhaps we should remove the needs repro script label from this issue now? I believe https://github.com/Automattic/mongoose/issues/6566#issuecomment-397935727 is a good start.

It’s not just the connection either, deleting, and creating data are 10x+ slower as well.

Using the following code:

const mongoose = require('mongoose');
const { Schema } = mongoose;
mongoose.Promise = Promise;


const userSchema = new Schema();

const User = mongoose.model('User', userSchema);

const users = [];

for (let i = 0; i < 1000; i++) users.push(new User());

const run = async () => {
  await mongoose.connect('mongodb://localhost/test');

  const before = Date.now();

  await User.remove();
  await User.create(users);

  const after = Date.now();

  console.log(`Duration: ${(after - before) / 1000}s`);
};

run().catch(console.error);

v4.13.14 outputs:

Duration: 0.461s

v5.1.5 outputs:

Duration: 4.621s