A High-Throughput and Low-Latency Parallelization of Window-based Stream Joins on Multicores

Data Stream Processing (DaSP) is a paradigm characterized by on-line (often real-time) applications working on unlimited data streams whose elements must be processed efficiently "on the fly". DaSP computations are characterized by data-flow graphs of operators connected via streams and working on the received elements according to high throughput and low latency requirements. To achieve these constraints, high-performance DaSP operators requires advanced parallelism models, as well related design and implementation techniques targeting multi-core architectures. In this paper we focus on the parallelization of the window-based stream join, an important operator that raises challenging issues in terms of parallel windows management. We review the state-of-the-art solutions about the stream join parallelization and we propose our novel parallel strategy and its implementation on multicores. As demonstrated by experimental results, our parallel solution introduces two important advantages with respect to the existing solutions: (i) it features an high-degree of configurability in order to address the symmetricity/ asymmetricity of input streams (in terms of their arrival rate and window length); (ii) our parallelization provides a high throughput and it is definitely better than the compared solutions in terms of latency, providing an efficient way to perform stream joins on latency-sensible applications.