I don't know why people keep submitting this garbage from Espresso Logic, who is just taking advantage of the fact the the term "reactive" has been overloaded to mean different things to exploit the hype surrounding the Reactive Manifesto and related technologies (e.g., Akka, Rx, Node.js, etc.) to push their own, completely unrelated product, which is based on the more traditional (i.e., the one you find in Wikipedia) definition of "Reactive Programming".
"Reactive programming", as defined by the Reactive Manifesto (which is what all the hype is about), is about designing applications that operate in an entirely asynchronous and non-blocking manner, so as to maximize CPU utilization and fully exploit parallelism, and ensure that the system is always responsive to new events (user input, incoming data streams, errors, changes in load, etc.) rather than having resources tied up waiting for external processes (e.g., blocking on I/O). It has nothing to do with "reactive databases".