Holistic Query Transformations for Dynamic Web Applications

A promising approach to scaling Web applications is to distribute the server infrastructure on which they run. This approach, unfortunately, can introduce latency between the application and database servers, which in turn increases the network latency of Web interactions for the clients (end users). In this paper we introduce the concept of source-to-source holistic transformations - transformations that seek to optimize both the application code and the database requests made by it, to reduce client latency. As examples of our concept, we propose and evaluate two source-to-source holistic transformations that focus on hiding the latencies of database queries. We argue that opportunities for applying these transformations will continue to exist in Web applications. We then present algorithms for automating these transformations in a source-to-source compiler. Finally, we evaluate the effect of these two transformations on three realistic Web benchmark applications, both in the traditional centralized setting and a distributed setting.