We discussed the hyper proxy modules for Active prefetching and lazy segmentation strategy. We continue discussing the remaining two modules.  We briefly looked at the replacement policy and the maintainance of two lists - basic and premium lists.  The utility value of each object is updated after each replacement. Even after an object is fully evicted,  the system will keep its access log.  If this is not the case, when the object is accessed again, it will be fully cached.One characteristic of media objects is that they have diminishing popularity as the time goes by. Hence this recaching the full length of the object is wasteful. Consequently keeping the access log is relevant and recommended.
To not let access logs proliferate, a large enough timeout threshold is set so that the proxy deletes the access logs eventually.
We now look at performance evaluation.  To evaluate the performance of the proxy, it was tested on several workloads - both real and synthetic. All the workloads assumed a Zipf like distribution with a skew factor of theta. All the media objects and the request interval follow the Poisson distribution with a mean interval lambda.
The first synthetic workload simulates accesses to the media object in the web environment in which the media varies from short one to long one. All there parameters are considered same.
The second workload simulates the web access where the clients abort the access where a started session terminates before the full media object is delivered.Nearly 80%of the sessions terminated before 20% of the object is delivered.
The third workload is a real capture of a workload covering a period of 10 days from an actual server.
There are a total of 403 objects and the unique object size accounts to 20GB. A total of 9000 requests were made during the period mentioned for the real workload.