An Evaluation of Document Prefetching in a Distributed Digital Library
Latency is a fundamental problem for all distributed systems
including digital libraries. To reduce user perceived delays both
caching -- keeping accessed objects for future use -- and
prefetching -- transferring objects ahead of access time -- can be
used. In a previous paper we have reported that caching is not
worthwhile for digital libraries due to low re-access frequencies.
In this paper we evaluate our previous findings that prefetching can
be used instead. To do this we have set up an experimental
prefetching proxy which is able to retrieve documents from remote
fulltext archives before the user demands them. Using a simple
prediction to keep the overhead of unnecessarily transfered data
limited, we find that it is possible to cut the user perceived
average delay a factor of two.