Spanner: Google’s global distributed database
Google’s Spanner is a distributed storage system project that for the first time has solved the issue of externally consistent transactions at global scale. It provides global distribution and replication of data to provide both high availability and to minimize latency of data reads and writes.
Google’s engineers have made an amazing job. They have created a virtual global wall clock, called TrueTime, which is used by the system to ensure the global transactions order. TrueTime exposes the uncertainty in the clock by representing time as an interval.
Mind map: Spanner DB(download)