On the Avoidance of the Double Paging Anomaly in Virtual Memory Systems
Khien Chew, Avi Silberschatz · 1992
A computer system that buffers data in a buffer-pool allocated in the virtual memory can experience the double paging anomaly that results in significant performance degradation. Existing techniques for avoiding this anomaly are not adequate when main memory is allocated dynamically or when very large buffer-pools are required. In this paper, we argue that in order to achieve good buffering performance in an environment where the buffer-pool cannot be fully allocated in main memory, the buffer-pool size should be set to be equal to the size of the database. A buffering system using this approach is referred to as a maximal-pool system. We define a new class of maximal-pool systems, referred to as symmetric maximal-pool systems, and show that such systems completely avoid the double paging anomaly. We also discuss how such maximal-pool systems can be implemented using suitably improved memory-mapped file facilities, and characterize the paging performance of buffering systems that use t...