What is an “optimal” cache size to avoid returning obsolete results?
Caching is now more popular than ever. (See our add-ons page for some of the more popular caching programs.) In general, a 1-month cache isn’t bad in terms of redundant results, but a 7-day cache is much better. An “optimal” cache (minimizing the likelihood that a result will have already passed integrity testing before you return it), however, shouldn’t hold more than a 2 days of workunits. In the past, 1 month was pretty safe, but the ramifications of Moore’s Law have made the cache window much smaller. Keep in mind, of course, that excepting the above case, redundancy is extremely important for testing the integrity of our data. Interestingly, even without cacheing, users on average will receive a duplicate workunit (one they’ve processed before) about once every 500 times.
