To cache or not to cache: a trade-off analysis for locally cached database systems

Abstract

In this paper, we study the feasibility of using performance models to support an analysis of the computational load in local database caching. Local database caching is used, for example, to relieve the computational load of a main DBMS in large deployments of web applications. This is done by caching part of the database contents in a DBMS local to the application server. While for common scenarios with a high browse-to-order ratio this frequently results in a reduction of the computational load, there are also scenarios in which there is not a clear advantage of local database caching. This is especially the case when each local write also results in a write into the main database server, thereby increasing the computational resource requirements. In this paper, two methods are presented which can be used to obtain significant computational parameters. We demonstrate how these parameters are used on two different hardware platforms and show that a reasonable prediction accuracy within actual measured results can be reached.