Mapping a billion stars throughout our Galaxy and beyond Gaia is a cornerstone European Space Agency mission that will create an extraordinarily precise three-dimensional map of more than a billion stars throughout our Galaxy and beyond, mapping their motions, luminosity, temperature and composition. This huge stellar census will provide the data needed to tackle an enormous range of important problems related to the origin, structure and evolutionary history of our Galaxy. I will describe how Variability Studies of light sources observed by Gaia pose Big Data problem that we are trying to solve with the help of Postgres-XC.