Web Caching and Replication

6.5. Locality of Reference

Uneven popularity distribution is a manifestation of locality of reference. Locality of reference characterizes the ability to predict future accesses to objects from past accesses. There are two main types of locality: temporal and spatial. Temporal locality refers to repeated accesses to the same object within short time periods. High temporal locality implies that recently accessed objects are likely to be accessed again in the future. Spatial locality refers to access patterns where accesses to some objects frequently entail accesses to certain other objects. For example, an access to an HTML page can entail accesses to objects embedded or hyperlinked in this page. High spatial locality implies that references to ...