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StagedDB: Designing Database Servers for Modern Hardware

Tuesday March 29, 2005
Hamerschlag Hall D-210
4:00 pm

Stavros Harizopoulos
Carnegie Mellon University

Advances in computer architecture research yield increasingly powerful processors which can execute code at a much faster pace than they can access data in the memory hierarchy. Database management systems (DBMS), due to their intensive data processing nature, are in the front line of commercial applications who cannot harness the available computing power. To prevent the CPU from idling, a multitude of hardware mechanisms and software optimizations have been proposed. Their effectiveness, however, is limited by the sheer volume of data accessed and by the unpredictable sequence of memory requests. Moreover, as more hardware-level parallelism becomes available through simultaneous multithreading (SMT) and chip multiprocessing (CMP), traditional DBMS architectures will face new challenges in utilizing additional hardware resources.

In this talk I describe StagedDB, a new DBMS software architecture for optimizing data and instruction locality at all levels of the memory hierarchy. The key idea is to break database request execution in stages and process a group of sub-requests at each stage, thus effortlessly exploiting data and work commonality. I present two systems based on the StagedDB design. QPipe, a staged relational query engine built on top of BerkeleyDB, maximizes data and work sharing across concurrent queries, providing up to 2x throughput speedup in a decision-support workload. STEPS, a transaction coordinating mechanism demonstrated on top of Shore, minimizes instruction-cache misses without increasing the cache size, eliminating two thirds of all instruction misses when running on-line transaction processing applications. By translating high concurrency into improved locality and by providing fine-grain software parallelism, the StagedDB architecture is a unique match to future highly-parallel infrastructures.

Stavros Harizopoulos is a Ph.D. candidate in the Department of Computer Science at Carnegie Mellon University, under the supervision of Professor Anastassia Ailamaki. He received his Diploma in Electrical and Computer Engineering from the Technical University of Crete, and his MS degree in Computer Science from Carnegie Mellon. His research focuses on improving database system performance by taking into account modern hardware architectures.


Department of Electrical and Computer EngineeringCarnegie Mellon UniversitySchool of Computer Science