Before you get any ideas, we’re talking about good old-fashioned database ACID compliance. ACID is not a new concept to developers. Certainly every DBA knows it, but collectively, the software industry lost its addiction to ACID some time ago.
This is because the industry found a new thing to crave: distributed computing. Internet giants like Google and Facebook created massive businesses that eclipsed the scale of anything traditional enterprises had done previously. They were smart and focused on a user experience that included performance. To reach a quarter of the planet it, was a given there would never be a single machine large enough to match the needed scale. Plus, their apps had already proven out a shared-nothing architecture. Rather than waste time trying to hack MySQL into bending to their will, they set out to find a different way to put their data in a distributed, shared-nothing architecture.
It turns out that having atomic transactions consistently committed and readable across distributed nodes AND always available was hard. These trade-offs are the crux of the well recognized conundrum that CAP Theorem summarizes. So when looking to build Apache Hadoop, the solutions to force ACID into its shared-nothing architecture were so out of reach that they were forced to truly gut check themselves, asking, “Does ACID really matter?”