Connection TTL

[tmszdmsk]

With the newly added release event in Pool, it is possible to implement connection TTL. We did that internally in our project but it would be great to have OOTB support for it in node-postgres.

It helped us resolve problems with AZ failovers when connecting to AWS RDS when the domain name starts pointing to different machine but connections in the pool still use previous address.

I wanted to understand whether there is any need for that before I start working on the PR. What do you think?

[sehrope]

There's a maxLifetimeSeconds property that's unfortunately not documented in the README. If set, it's a max duration in seconds to keep the client around. Here's the property:

node-postgres/packages/pg-pool/index.js

Lines 254 to 275 in b357e18

	if (this.options.maxLifetimeSeconds !== 0) {
	const maxLifetimeTimeout = setTimeout(() => {
	this.log('ending client due to expired lifetime')
	this._expired.add(client)
	const idleIndex = this._idle.findIndex((idleItem) => idleItem.client === client)
	if (idleIndex !== -1) {
	this._acquireClient(
	client,
	new PendingItem((err, client, clientRelease) => clientRelease()),
	idleListener,
	false
	)
	}
	}, this.options.maxLifetimeSeconds * 1000)
	maxLifetimeTimeout.unref()
	client.once('end', () => clearTimeout(maxLifetimeTimeout))
	}
	return this._acquireClient(client, pendingItem, idleListener, true)
	}
	})

Here's the PR that added it: #2698

It might cover the use case you are describing.