The increases in main-memory sizes over the last decade have made pure in-memory database systems feasible, and in-memory systems offer unprecedented performance. However, DRAM is still relatively expensive, and the growth of main-memory sizes has slowed down. In contrast, the prices for SSDs have fallen substantially in the last years, and their read bandwidth has increased to gigabytes per second. This makes it attractive to combine a large in-memory buffer with fast SSDs as storage devices, combining the excellent performance for the in-memory working set with the scalability of a disk-based system.

The Umbra system is an evolution of the pure in-memory HyPer system towards a disk-based, or rather SSD-based, system. By using a novel low-overhead buffer manager with variable-size pages we can achieve comparable performance to an in-memory database system for the cached working set, while handling accesses to uncached data gracefully. A combination of compilation and optimization techniques allows for handling very large and very complex queries with low latency, which is essential for interactive data exploration.

This talk is part of the ¡Databases! – A Database Seminar Series.

Bio:
Thomas Neumann is a full professor in the Department of Computer Science at the Technical University of Munich. After his PhD in Computer Science at the University of Mannheim in 2005, he was Senior Researcher at the Max-Planck Institute for Informatics in Saarbrücken until 2010. His research interests are in the areas of database systems, query processing, and query optimization. In 2020, he received the Gottfried Wilhelm Leibniz Prize.

More Info: https://db.cs.cmu.edu/seminar2022#db1