The basic problem they're trying to solve is the difficulty of scaling today's RDBMS systems across potentially massive clusters of commodity x86 servers, and doing so in a way that's "elastic," so that an organization can scale its infrastructure up and down as demand requires.

"The essential problem, as I see it, is that existing relational database management systems just flat-out don't scale," said Jim Starkey, a former senior architect at MySQL and one of the original developers of relational databases.

Starkey is founder and CTO of NimbusDB, which is trying to address those problems with a "radical restart" of relational database technology. Its software has "nothing in common with pre-existing systems," according to Starkey, except that developers can still use the standard SQL query language.

NimbusDB aims to provide database software that can scale simply by "plugging in" new hardware, and that allows a large number of databases to be managed "automatically" in a distributed environment, he said. Developers should be able to start small, developing an application on a local machine, and then transfer their database to a public cloud without having to take it offline, he said.

"One of the big advantages of cloud computing is you don't have to make all the decisions up front. You start with what's easy and transition into another environment without having to go offline," he said.