Efficient data discovery is crucial in the era of data-driven decisionmaking. However, current practices face significant challenges due to the intricacies of identifying datasets with specific distributional characteristics, such as percentiles, when data repositories are decentralized. Traditional keyword-based search methods are insufficient for these complex requirements, often resulting in suboptimal dataset search results. To address these challenges, this paper presents Fainder, a fast and accurate index for "percentile predicates" on histogram-based data summaries, which streamlines the search process for datasets with specific distributional requirements. Fainder can be constructed on heterogeneous histogram collections and employs binary search in conjunction with multi-step pruning techniques to efficiently identify search results for percentile predicates. Thereby, it simplifies data provisioning and improves the effectiveness of dataset discovery. Empirical evaluation of our solution on three large-scale data repositories shows that Fainder is effective for distribution-aware dataset search and provides order-of-magnitude efficiency gains over baselines.

Training deep learning (DL) models often takes a significant amount of time and is thus typically performed on expensive GPUs to speed up the process. However, data loading has recently been identified as one of the main performance bottlenecks in DL, resulting in GPU under-utilization. Looking forward, the combination of larger datasets and faster GPUs will exacerbate the problem. The data management community has started to address this by proposing data loading optimization techniques, including lossy image compression. While lossy compression is a conceptually promising approach for mitigating data loading bottlenecks in DL, there is only limited understanding of its efficacy in terms of impact on model throughput and accuracy. In this paper, we present an extensive experimental analysis of lossy image compression as a means to improve the performance of neural network training. We find that lossy compression can improve both throughput and accuracy of DL pipelines if resources such as time or storage capacity are limited. Furthermore, the choice of compression quality and codec are important hyperparameters when training deep neural networks.