A Design Space Exploration and Evaluation for Main-Memory Hash Joins in Storage Class Memory

In this paper, we seek to perform a rigorous experimental study of main-memory hash joins in storage class memory (SCM). In particular, we perform a design space exploration in real SCM for two state-of-the-art join algorithms: partitioned hash join (PHJ) and non-partitioned hash join (NPHJ), and identify the most crucial factors to implement an SCM-friendly join. Moreover, we present a rigorous evaluation with a broad spectrum of workloads for both joins and provide an in-depth analysis for choosing the most suitable algorithm in real SCM environment. With the most extensive experimental analysis up-to-date, we maintain that although there is no one universal winner in all scenarios, PHJ is generally superior to NPHJ in real SCM.