Spanner, the Google Database That Mastered Time, Is Now Open to Everyone
A DECADE ago, a handful of #Google ’s most talented engineers started building a system that seems to defy logic. Called #Spanner, it was the first global database, a way of storing information across millions of machines in dozens of data centers spanning multiple continents, and it now underpins everything from Gmail to AdWords, the company’s primary moneymaker. But it’s not just the size of this creation that boggles the mind. The real trick is that, even though Spanner stretches across the globe, it behaves as if it’s in one place. Google can change company data in one part of this database—running an ad, say, or debiting an advertiser’s account—without contradicting changes made on the other side of the planet. What’s more, it can readily and reliably replicate data across multiple data centers in multiple parts of the world—and seamlessly retrieve these copies if any one data center goes down. For a truly global business like Google, such transcontinental consistency is enormously powerful.