Clocks and Causality – Ordering Events in Distributed Systems (2022)
> However, because of clock drifts and/or assumptions around network time delays, timestamps from conventional clocks are not always mutually comparable, and therefore events cannot be reliably ordered using timestamps from conventional clocks.This isn’t quite right. CockroachDB and Yuggabyte both use conventional clocks to reliably order events. Spanner uses GPS to do so (conventional time stamp but maybe not technically a conventional clock).