Modern servers have become heterogeneous, often combining multi-core CPUs with many-core GPUs. Such heterogeneous architectures have the potential to improve the performance of data-intensive stream processing applications, but they are not supported by current relational stream processing engines. For an engine to exploit a heterogeneous architecture, it must execute streaming SQL queries with sufficient data-parallelism to fully utilise all available heterogeneous processors, and decide how to use each in the most effective way. It must do this while respecting the semantics of streaming SQL queries, in particular with regard to window handling.

In this talk, I describe SABER, a hybrid high-performance relational stream processing engine for CPUs and GPUs. SABER executes window-based streaming SQL queries in a data-parallel fashion using all available CPU and GPU cores. Instead of statically assigning query operators to heterogeneous processors, SABER employs a new adaptive heterogeneous lookahead scheduling strategy, which increases the share of operators executing on the processor that yields the highest performance. To hide data movement costs, SABER pipelines the transfer of stream data between CPU and GPU memory. Our experimental comparison against state-of-the-art engines shows that SABER increases processing throughput while maintaining low latency for a wide range of streaming SQL queries with both small and large window sizes.

Alexandros Koliousis is a Research Associate at the Department of Computing, Imperial College London. He is a member of the Large-Scale Distributed Systems groups. His research is currently focused on engineering data parallel processing systems (e.g. for stream processing) that make best use of heterogeneous processors. Prior to joining Imperial College, he was working on home network management at the School of Computing Science, University of Glasgow, from where he also obtained his MSc and PhD degrees.