TrioStat: Online Workload Estimation in Distributed Spatial Data Streaming Systems.

The wide spread of GPS-enabled devices and the Internet of Things (IoT) has increased the amount of spatial data being generated every second. The current scale of spatial data cannot be handled using centralized systems. This has led to the development of distributed spatial data streaming systems that scale to process in real-time large amounts of streamed spatial data. The performance of distributed streaming systems relies on how even the workload is distributed among their machines. However, it is challenging to estimate the workload of each machine because spatial data and query streams are skewed and rapidly change with time and users' interests. Moreover, a distributed spatial streaming system often does not maintain a global system workload state because it requires high network and processing overheads to be collected from the machines in the system.This paper introduces TrioStat; an online workload estimation technique that relies on a probabilistic model for estimating the workload of partitions and machines in a distributed spatial data streaming system. It is infeasible to collect and exchange statistics with a centralized unit because it requires high network overhead. Instead, TrioStat uses a decentralised technique to collect and maintain the required statistics in real-time locally in each machine. TrioStat enables distributed spatial data streaming systems to compare the workloads of machines as well as the workloads of data partitions. TrioStat requires minimal network and storage overhead. Moreover, the required storage is distributed across the system's machines.