There has been a growing demand for making modern cloud-based data analytics systems cost-effective and easy to use. AI-powered intelligent resource scaling is one such effort, aiming at automating scaling decisions for serverless offerings like Amazon Redshift Serverless. The foundation of intelligent resource scaling lies in the ability to forecast query workloads and their resource consumption accurately. Although the forecasting problem has been extensively studied across various domains, there is a lack of thorough analysis of existing forecasting algorithms for large-scale, real-world cloud query workloads. This paper fills this gap by providing an in-depth analysis of forecasting algorithms for real-world cloud workloads, covering the fundamental data characteristics that distinguish query workload forecasting from prior problems and evaluating the strengths and limitations of existing algorithms in this new domain. We anticipate that our findings will provide valuable insights in informing the design of an efficient and effective solution for production use, as well as in steering the forecasting community toward more effective algorithms of high real-world impact.

Modern data systems are typically both complex and general-purpose. They are complex because of the numerous internal knobs and parameters that users need to manually tune in order to achieve good performance; they are general-purpose because they are designed to handle diverse use cases, and therefore often do not achieve the best possible performance for any specific use case. A recent trend aims to tackle these pitfalls: instance-optimized systems are designed to automatically self-adjust in order to achieve the best performance for a specific use case, i.e., a dataset and query workload. Thus far, the research community has focused on creating instance-optimized database components, such as learned indexes and learned cardinality estimators, which are evaluated in isolation. However, to the best of our knowledge, there is no complete data system built with instance-optimization as a foundational design principle. In this paper, we present a progress report on SageDB, our effort towards building the first instance-optimized data system. SageDB synthesizes various instance-optimization techniques to automatically specialize for a given use case, while simultaneously exposing a simple user interface that places minimal technical burden on the user. Our prototype outperforms a commercial cloud-based analytics system by up to 3X on end-to-end query workloads and up to 250X on individual queries. SageDB is an ongoing research effort, and we highlight our lessons learned and key directions for future work.

Scanning and filtering over multi-dimensional tables are key operations in modern analytical database engines. To optimize the performance of these operations, databases often create clustered indexes over a single dimension or multi-dimensional indexes such as R-Trees, or use complex sort orders (e.g., Z-ordering). However, these schemes are often hard to tune and their performance is inconsistent across different datasets and queries. In this paper, we introduce Flood, a multi-dimensional in-memory read-optimized index that automatically adapts itself to a particular dataset and workload by jointly optimizing the index structure and data storage layout. Flood achieves up to three orders of magnitude faster performance for range scans with predicates than state-of-the-art multi-dimensional indexes or sort orders on real-world datasets and workloads. Our work serves as a building block towards an end-to-end learned database system.

Filtering data based on predicates is one of the most fundamental operations for any modern data warehouse. Techniques to accelerate the execution of filter expressions include clustered indexes, specialized sort orders (e.g., Z-order), multi-dimensional indexes, and, for high selectivity queries, secondary indexes. However, these schemes are hard to tune and their performance is inconsistent. Recent work on learned multi-dimensional indexes has introduced the idea of automatically optimizing an index for a particular dataset and workload. However, the performance of that work suffers in the presence of correlated data and skewed query workloads, both of which are common in real applications. In this paper, we introduce Tsunami, which addresses these limitations to achieve up to 6X faster query performance and up to 8X smaller index size than existing learned multi-dimensional indexes, in addition to up to 11X faster query performance and 170X smaller index size than optimally-tuned traditional indexes.

We present Park, a platform for researchers to experiment with Reinforcement Learning (RL) for computer systems. Using RL for improving the performance of systems has a lot of potential, but is also in many ways very different from, for example, using RL for games. Thus, in this work we first discuss the unique challenges RL for systems has, and then propose Park an open extensible platform, which makes it easier for ML researchers to work on systems problems. Currently, Park consists of 12 real world system-centric optimization problems with one common easy to use interface. Finally, we present the performance of existing RL approaches over those 12 problems and outline potential areas of future work.

The growth of video traffic makes it increasingly likely that multiple clients share a bottleneck link, giving video content providers an opportunity to optimize the experience of multiple users jointly. But today's transport protocols are oblivious to video streaming applications and provide only connection-level fairness. We design and build Minerva, the first end-to-end transport protocol for multi-user video streaming. Minerva uses information about the player state and video characteristics to adjust its congestion control behavior to optimize for QoE fairness. Minerva clients receive no explicit information about other video clients, yet when multiple of them share a bottleneck link, their rates converge to a bandwidth allocation that maximizes QoE fairness. At the same time, Minerva videos occupy only their fair share of the bottleneck link bandwidth, competing fairly with existing TCP traffic. We implement Minerva on an industry standard video player and server and show that, compared to Cubic and BBR, 15-32%of the videos using Minerva experience an improvement in viewing experience equivalent to a jump in resolution from 720p to 1080p. Additionally, in a scenario with dynamic video arrivals and departures, Minerva reduces rebuffering time by an average of 47%.

Network performance monitoring today is restricted by existing switch support for measurement, forcing operators to rely heavily on endpoints with poor visibility into the network core. Switch vendors have added progressively more monitoring features to switches, but the current trajectory of adding specific features is unsustainable given the ever-changing demands of network operators. Instead, we ask what switch hardware primitives are required to support an expressive language of network performance questions. We believe that the resulting switch hardware design could address a wide variety of current and future performance monitoring needs.

Diagnosing performance problems in networks is important, for example to determine where packets experience high latency or loss. However, existing performance diagnoses are constrained by limited switch mechanisms for measurement. Alternatively, operators use endpoint information indirectly to infer root causes for problematic latency or drops.