Object and File Management in the EXODUS Extensible Database System

摘要

This paper describes the design of the object-oriented storage component of EXODUS, an extensible database management system currently under development at the University of Wisconsin. The basic abstraction in the EXODUS storage system is the storage object, an uninterpreted variable-length record of arbitrary size; higher level abstractions such as records and indices are supported via the storage object abstraction. One of the key design features described here is a scheme for managing large dynamic objects, as storage objects can occupy many disk pages and can grow or shrink at arbitrary points. The data structure and algorithms used to support such objects are described, and performance results from a preliminary prototype of the EXODUS large-object management scheme are presented. A scheme for maintaining versions of large objects is also described. The file structure used in the EXODUS storage system, which provides a mechanism for grouping and sequencing through a set of related storage objects and the EXODUS approach to buffer management, concurrency control, and recovery, both for small and large objects are discussed. 30 refs., 13 figs. (ERA citation 11:053071)