Application-controlled file caching policies
USTC'94 Proceedings of the USENIX Summer 1994 Technical Conference on USENIX Summer 1994 Technical Conference - Volume 1
Implementation and performance of application-controlled file caching
OSDI '94 Proceedings of the 1st USENIX conference on Operating Systems Design and Implementation
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The buffering facilities typically provided by operating systems are not powerful enough to support the performance and consistency requirements of database systems. As a result, most database systems are structured as Buffer Pool Database (BPDB) systems, providing their own buffering facilities, with their own paging policies and recovery schemes. The emergence of operating systems with very large address spaces and flexible memory management makes Virtual Memory Database (VMDB) systems feasible. In such systems, the database is mapped into virtual memory and the buffering facilities of the underlying virtual memory system are used. VMDB systems do not experience many of the problems faced by BPDB systems. To support the consistency and recoverability requirements of VMDB systems, we have proposed that the virtual memory system be extended to support the Recoverable-Persistent Updates (RPU) model. This model is powerful and general enough to support a wide variety of policies for ensuring database recoverability. In this paper we discuss our approach to and progress in extending the Mach 3.0 kernel to provide direct support for this RPU model.