How to implement reconnecting in Payload CMS if the db connection is disconnected?

[MurzNN]

After a long time of inactivity of the Payload CMS queries to the database, I see an error on every new request to the database:

MongoNotConnectedError: Client must be connected before running operations

Restarting the Payload instance helps resolve this issue. But it would still be great to have automatic reconnection to the database if the connection is disconnected. Maybe there is an option to enable automatic reconnection, instead of throwing an error?

[zubricks]

Hey @MurzNN absolutely there is! I took a quick breeze through the mongo docs and it looks like there is a solution. For reference: https://www.mongodb.com/docs/manual/reference/connection-string-options/

Payload passes connectOptions directly to Mongoose, so you can tune the MongoDB driver's connection behavior to handle this. The most effective options for keeping the connection alive are heartbeatFrequencyMS and minPoolSize:

import { mongooseAdapter } from '@payloadcms/db-mongodb'

mongooseAdapter({
  url: process.env.MONGODB_URI,
  connectOptions: {
    heartbeatFrequencyMS: 10000,
    minPoolSize: 1,
    serverSelectionTimeoutMS: 30000,
  },
})

minPoolSize: 1 is the key option here — it tells the driver to maintain at least one open connection, which would keep it from going completely idle and disconnecting like you're running into.

If you're running behind a proxy (AWS, nginx, etc.) that closes idle TCP connections after a timeout, you may also need to set socketTimeoutMS to a value lower than the proxy's idle timeout to force the driver to cycle connections before they're silently dropped.

If none of the above helps, it's worth checking whether the MongoDB server (or Atlas) has an idle connection timeout configured on its side.

[itxashancode]

If the MongoDB connection drops after inactivity, that's the driver's serverSelectionTimeoutMS kicking in. Payload just forwards whatever you put in connectOptions, so bump that timeout and enable autoReconnect:

// payload.config.js
module.exports = {
 mongo: {
 uri: process.env.MONGO_URI,
 options: {
 connectOptions: {
 serverSelectionTimeoutMS: 30000, // default is 30s
 autoReconnect: true,
 reconnectTries: Number.MAX_VALUE,
 reconnectInterval: 1000,
 },
 },
 },
};

Also make sure your MongoDB server isn't killing idle connections - set maxIdleTimeMS: 0 if you control the server, or use a connection pooler like ProxySQL/Atlas. If you're on a cloud provider, check their idle timeout settings.

[MurzNN]

Thank you, this setting works and helped investigate the real issue! The issue was with stale references to the Payload instance in the dev mode, when I change something - Payload reinitiate the instance, but in some functions there were a reference to the previous Payload instance, that already closed the connection.

Reworking this to always getting the fresh instance resolved the "Client must be connected before running operations" (also sometimes it showed "MongoTopologyClosedError: Topology is closed" error, so sharing the details here to help others who face the same error.

[itxashancode]

Glad it helped! 😊
A follow would mean a lot, always happy to connect with people building cool things!