View Invalidation for Dynamic Content Caching in Multitiered Architectures

In today's multitiered application architectures, clients do not access data stored in the databases directly. Instead, they use applications which in turn invoke the DBMS to generate the relevant content. Since executing application programs may require signi cant time and other resources, it is more advantageous to cache application results in a result cache. Various view materialization and update management techniques have been proposed to deal with updates to the underlying data. These techniques guarantee that the cached results are always consistent with the underlying data. Several applications, including e-commerce sites, on the other hand, do not require the caches be consistent all the time. Instead, they require that all out-dated pages in the caches are invalidated in a timely fashion. In this paper, we show that invalidation is inherently di erent from view maintenance. We develop algorithms that benet from this di erence in reducing the cost of update management in certain applications and we present an invalidation framework that bene ts from these algorithms.