Efficient view maintenance in a large-scale web warehouse

Web warehouse presents high availability and efficiency by utilizing materialized webviews, which must be refreshed periodically to keep freshness. Traditionally, there are three ways to refresh webviews: eager-update, lazy-update and minimum-updates. Due to limited resources and network, however, it is difficult for these approaches to balance well as the number of webviews and the capability of the web warehouse are rapidly increasing. In this scenario, our goal is to find more efficient techniques for the refreshing of webviews. In this paper we propose a method to minimize the unnecessary updates for materialized views without increasing of response time. This method, which is named VMOST (View Maintenance based On State Transferring), introduces four states for materialized webviews. When receiving query/update requests, webviews transfer between the four states in accordance with their accessing and changing history. According to the experimental data, VMOST is adaptive to the fast changing web environment and has a good overall performance.EI