The Case for In-Memory OLAP on "Wimpy" Nodes

Research projects will often use the latest hardware to achieve orders-of-magnitude performance improvements while ignoring the (usually hefty) associated price tag. Real-world deployments typically follow suit, requiring expensive computing infrastructures that cost even more to power and cool.In this paper, we challenge the conventional wisdom that high-end hardware is absolutely necessary for state-of-the-art performance and instead advocate for a radically different approach based on cheap single-board computers (SBCs). While others have previously explored similar ideas for computationally simple and easily partitionable use cases (e.g., key-value stores), so-called "wimpy" nodes have traditionally been rejected as unsuitable for more complex workloads. We believe, however, that recent hardware advancements driven by the mobile computing market call this orthodoxy into question. For example, our microbenchmarks show that one popular SBC, the Raspberry Pi 3B+, offers single-core compute performance that is surprisingly competitive with many server-grade Intel Xeon and ARM-based CPUs at a fraction of the cost and energy consumption.To make our case, we conducted an extensive experimental study, beginning with a series of microbenchmarks to identify the strengths and weaknesses of SBCs relative to server-grade CPUs. Then, to evaluate the ability of SBCs to handle more complex use cases, we analyzed the performance of an in-memory OLAP workload in both single-node and distributed settings. Overall, our results demonstrate up to several orders of magnitude in cost reductions coupled with substantial energy savings when compared to traditional on-premises and cloud deployments, all without a significant increase in absolute runtimes.