The problem of bu er management in database management systems is concerned with the e cient main memory allocation and management for answering database queries. Previous works on bu er allocation are based either exclusively on the availability of bu ers at runtime or on the access patterns of queries. In this paper, we rst propose a uni ed approach for bu er allocation in which both of these considerations are taken into account. Our approach is based on the notion of marginal gains which specify the expected reduction in page faults by allocating extra bu ers to a query. Then, we extend this approach to support adaptable bu er allocation. An adaptable bu er allocation algorithm automatically optimizes itself for the speci c query workload. To achieve this adaptability, we propose using run-time information, such as the load of the system, in bu er allocation decisions. Our approach is to use a simple queueing model to predict whether a bu er allocation will improve the performance of the system. Thus, this paper provides a more theoretical basis for bu er allocation. Simulation results show that our methods based on marginal gains and our predictive methods consistently outperform existing allocation strategies. In addition, the predictive methods have the added advantage of adjusting their allocation to changing workloads.
This is a notion similar to that of marginal gain used in database buffer allocation in REF .
Flexible and Adaptable Buffer Management Techniques for Database Management Systems
IEEE Transactions on Computers
Computer Science