Nice find.

If Postgres is already a single point of failure in the cluster, there’s not much sense in alsp having etcd as a dependency.

Relevant issue from 2022:
https://github.com/lightningnetwork/lnd/issues/6894

031ef7d322

I would guess it’s more common for application developers to reach for a tool more specific to the use case, like etcd, zookeeper, or consul. 

You’re right that LND could potentially use advisory locks, which might make sense to eliminate an entire dependency when postgres is used as the backend.

https://www.postgresql.org/docs/current/explicit-locking.html#ADVISORY-LOCKS

lightning

Highly available Lightning node cluster setup guide

Filiprogrammer

> Is leader election supported for Postgres?
>
>No, leader election is not supported by Postgres itself since it doesn't have a mechanism to reliably determine a leading node. It is, however, possible to use Postgres as the LND database backend while using an etcd cluster purely for the leader election functionality.

This is wrong though. You can construct something like an expiring lock in Postgres.