MaxListenersExceededWarning

[barrydevp]

Do you want to request a feature or report a bug?
bug

What is the current behavior?
Using useDb for reuse connection to replicaset mongodb server in multi-tenant architecture, after call useDb for 100 different database names. The nodejs Warning occur:

(node:35699) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 close listeners added to [MongoClient]. Use emitter.setMaxListeners() to increase limit
(node:35699) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 timeout listeners added to [MongoClient]. Use emitter.setMaxListeners() to increase limit
(node:35699) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 error listeners added to [MongoClient]. Use emitter.setMaxListeners() to increase limit
(node:35699) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 parseError listeners added to [MongoClient]. Use emitter.setMaxListeners() to increase limit

If the current behavior is a bug, please provide the steps to reproduce.

const conn = mongoose.createConnection(uri, {
           useUnifiedTopology: true,
})

for(let i = 0; i < 100; i++) {
       const db = conn.useDb(`db_${i}`)
}

What is the expected behavior?
The warning was not shown

What are the versions of Node.js, Mongoose and MongoDB you are using? Note that "latest" is not a version.
Nodejs: 12.22.1
mongoose: 5.13.9

[IslandRhythms]

So it reproduces on both 5.13.9 and latest, however, the error message prints once on latest whereas it prints 4 times on 5.13.9. How do you want to proceed @vkarpov15

const mongoose = require('mongoose');

async function test() {
   const conn = await mongoose.createConnection('mongodb://localhost:27017/', {
    useUnifiedTopology: true});
    for(let i = 0; i < 100; i++) {
        const db = conn.useDb(`db_${i}`);
    }
}


test();

[barrydevp]

Can you guys fix on the top of version 5.x, for some reason we cannot upgrade to version 6.x :( tks.