That common approach is both elegant and tricky. It requires very precise clocks and time synchronization, as some non-commutative operations are order-dependen

That common approach is both elegant and tricky. It requires very precise clocks and time synchronization, as some non-commutative operations are order-dependent (such as list insertion). That is why Google's TrueTime API (introduced in Spanner[0]) is such a big deal. [0]: http://static.googleusercontent.com/external_content/untrusted_dlcp/research.google.com/en/us/archive/spanner-osdi2012.pdf http://static.googleusercontent.com/external_content/untrust...