Hey guys,

My app is using mongoose on top of mongodb. Today, we got a spike with 100 users at the same time and I reached the 1500 connections limit of my Mongo Atlas instance (M10). Btw, on my homepage i've 7 different calls to the same serverless fn with different query params.

So far, i feel like anytime a request is made, a new connection is created and last for a couple of minutes.

I tried different approach even this one (https://github.com/vercel/mongodb-starter/tree/main), but nothing is making it better.

Does anyone is able to share its experience about this issue ?

Here is my mongoose config file and an example of how i'm using it in a simple request.

// mongoose.ts - Lib mongoose

import mongoose, { Mongoose } from "mongoose";

const MONGODB_URI = process.env.MONGODB_URI as string;

const options = {};

class Singleton {
  private static _instance: Singleton;
  private clientPromise: Promise<Mongoose>;
  private constructor() {
    this.clientPromise = mongoose.connect(MONGODB_URI).then((mongoose) => {
      console.log("Mongoose connection created");
      return mongoose;
    });
  }

  public static get instance() {
    if (!this._instance) {
      this._instance = new Singleton();
    }
    return this._instance.clientPromise;
  }
}
const clientPromise = Singleton.instance;

// Export a module-scoped MongoClient promise. By doing this in a
// separate module, the client can be shared across functions.
export default clientPromise;

// /api/live.ts - A simple example
import clientPromise from "@/database/mongoose";
import User from "@/models/User";
import type { NextApiRequest, NextApiResponse } from "next";

export default async function handler(
  req: NextApiRequest,
  res: NextApiResponse
) {
  if (req.method !== "GET") {
    res.status(404).end();
    return;
  }

  await clientPromise;

  const count = await User.find({ isLive: true }).count();

  res.status(200).json(count);
}

Thanks for your help!