Abstract

When implementing persistent objects on a relational database, a major performance issue is prefetching data to minimize the number of roundtrips to the database. This is especially hard with navigational applications, since future accesses are unpredictable. We propose using the context in which an object is loaded as a predictor of future accesses, where context can be a stored collection of relationships, a query result, or a complex object. When an object O's state is loaded, similar state for other objects in O's context is prefetched. We present a design for maintaining context and using it to guide prefetch. We give performance measurements of its implementation in Microsoft Repository, showing up to a 70% reduction in running time. We describe variations that selectively apply the technique, exploit asynchronous access, and use application-supplied performance hints. 1 Introduction One way to implement persistent objects is to map them to a relational databas...

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