Towards an Explicitation and a Conceptualization of Cost Models in Database Systems

In the database landscape, the mathematical cost models play a crucial role in evaluating non-functional requirements such as the query execution performance, energy consumption, monetary cost estimation. The development of a such cost model is time consuming and requires the knowledge of the whole environment of database systems. Also, cost models are scattered either in scientific papers, usually with fewer details or inside commercial and academic database management systems. Therefore, cost models become a dark entity, because they cannot be easily exploited by researchers and students for learning, analysis or reproduction purposes. In this paper, first we aim to increase the awareness about the darkness of cost models. Secondly, thanks to meta modeling techniques, we explicit the different dimensions of cost models. Persisting the cost models in a repository via a user-friendly interface is also described and stressed through several usage scenarios.