Document Updates - Do updates with no changes still cost 1 write?

Question

Do document updates, where the update from a client, has no difference with the Firestore server copy still cost in terms of number of writes?

Also would a cloud fun

Answer 1

Document updates all incur billing for a write. But Cloud Functions and realtime listeners will not be invoked if data doesn't actually change in the document. The only situation where I suspect a listener might be invoked is if the client itself attempts to make an update to the same document it's listening to, but I'm not sure about that.