Google’s Spanner: A database that knows what time it is — Data | GigaOM: "Google has made public the details of its Spanner database technology, which allows a database to store data across multiple data centers, millions of machines and trillions of rows. But it’s not just larger than the average database, Spanner also allows applications that use the database to dictate where specific data is stored so as to reduce latency when retrieving it.
Making this whole concept work is what Google calls its True Time API, which combines an atomic clock and a GPS clock to timestamp data so it can then be synched across as many data centers and machines as needed. From the Google paper:"
