Google announced that Cloud Spanner, its globally distributed relational database service, is generally available after a relatively short four-month beta period.
Spanner was the first global database which stores information across millions of machines in dozens of data centers spanning multiple continents. It underpins many things from Google, including Gmail to AdWords, Google Photos and the Google Play store.
What makes Spanner unique is that even though it stretches across the globe, it behaves as if it's in one place. This way, Google can exchange data from one part of the database, like running an advertisement, for example, 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 if anything goes wrong, like when one data center goes offline, for example, Spanner can seamlessly retrieve copies.
Without Spanner, this was seemed to be impossible. The reason is because computers couldn't keep databases consistent without constant communication. And given by the size of the Earth and Google, communication for a lot of data can take a very long time.
For Google, this was a problem. If a database spanned multiple regions, the company couldn't ensure that transactions in one part of the world lined up with transactions in another. With Spanner, Google's engineers found a way to trust time.
And with the many advantages Google has enjoyed, the company is offering this technology to the rest of the world as a cloud computing service.
One of the tricks that Spanner has, is providing Google's data centers with a series of GPS receivers and atomic clocks. The GPS receivers grab the time from various satellites orbiting the globe, while the atomic clocks keep their own time.
Then they shuttle their time readings to master servers in each data center. These masters constantly trade readings in an effort to settle on a common time.
While error still exists, with so many data to fiddle with, Spanner can bootstrap a far more reliable timekeeping service. "This gives you faster-than-light coordination between two places," said Peter Mattis, a former Google engineer who founded CockroachDB, a startup working to build an open source version of Spanner.
Google calls this timekeeping technology TrueTime.
When it was first launched, Google positioned Spanner as an alternative for businesses that were outgrowing their existing databases.
"If you are struggling with the scale of your transactional database — you will go to a sharded database, or NoSQL," said Google’s Deepti Srivastava "If you’re at that stage where you have to make those trade-offs, Spanner is the way to go. You are already doing work to use one of those systems. We try to make that trade-off as simple as possible.”
With Spanner generally available, Google promises its users a 99.999 percent availability and strong consistency.
"As a combined software/hardware solution that includes atomic clocks and GPS receivers across Google’s global network, Cloud Spanner also offers additional accuracy, reliability and performance in the form of a fully-managed cloud database service," claimed Google.
Google believes by having Spanner with TrueTime technology available to the public, the strategy can help its attempt in competing with Microsoft and Amazon for supremacy in the increasingly important cloud computing market.