MiSTRAL: An architecture for low-latency analytics on MasSive time series

Smart sensors are increasingly being used to manage and monitor critical urban infrastructures, e.g., for telecommunication, transport, water, or energy networks, as well as for healthcare or smart buildings. Sensor-based monitoring systems offer ways of continuously monitoring low frequency activities, and open the door to new analytic and predictive applications in Smarter Cities. Such sensors generate “tricklets”, i.e., noisy and continuous time series. Tricklets are typically misaligned, non-uniformly sampled, and comprise low frequency activities and recurring patterns. Storing and making sense of such data in a typical database management system is difficult, due to the impedance mismatch between classical (e.g., relational) data and tricklets. In this paper, we investigate the management of large amounts of tricklets from an architectural perspective, and propose MiSTRAL (MaSsive TRicklets anALysis), an architecture designed for executing low-latency analytics on time series warehouses. MiSTRAL uses a dictionary based representation for tricklets that allows queries to be run natively on compressed representations and thus to achieve the low-latency goal. The architecture of MiSTRAL is presented in detail in the following, along with early experimental results on several Smarter Cities datasets.