Low-Latency Handshake Join

This work revisits the processing of stream joins on modern hardware architectures. Our work is based on the recently proposed handshake join algorithm, which is a mechanism to parallelize the processing of stream joins in a NUMA-aware and hardware-friendly manner. Handshake join achieves high throughput and scalability, but it suffers from a high latency penalty and a non-deterministic ordering of the tuples in the physical result stream. In this paper, we first characterize the latency behavior of the handshake join and then propose a new low-latency handshake join algorithm, which substantially reduces latency without sacrificing throughput or scalability. We also present a technique to generate punctuated result streams with very little overhead; such punctuations allow the generation of correctly ordered physical output streams with negligible effect on overall throughput and latency.