PTP/TrueTime vs. HLC when it comes to snapshots

Google's Spanner paper was published in 2012 which famously introduced the TrueTime API. PTP is the standard equivalent of TrueTime. Two years later, Kulkarni, et al. published the Hybrid Logical Clock paper – Logical Physical Clocks and Consistent Snapshots in Globally Distributed Databases. In the HLC paper, they list the downsides…