Scheduling strategies for processing continuous queries over streams

Stream data processing poses many challenges. Two important characteristics of stream data processing - bursty arrival rates and the need for near real-time performance requirement - challenge the allocation of limited resources in the system. Several scheduling algorithms (e.g., Chain strategy) have been proposed for minimizing the maximal memory requirements in the literature. In this paper, we propose novel scheduling strategies to minimize tuple latency as well as total memory requirement. We first introduce a path capacity strategy (PCS) with the goal of minimizing tuple latency. We then compare the PCS and the Chain strategy to identify their limitations and propose additional scheduling strategies that improve upon them. Specifically, we introduce a segment strategy (SS) with the goal of minimizing the memory requirement, and its simplified version. In addition, we introduce a hybrid strategy, termed the threshold strategy (TS), to addresses the combined optimization of both tuple latency and memory requirement. Finally, we present the results of a wide range of experiments conducted to evaluate the efficiency and the effectiveness of the proposed scheduling strategies.