Data Stream Operations as First-Class Entities in Palladio

Abstract

The Palladio Component Model (PCM) is an approach to simulate the performance of software systems using a component-based modeling language. When simulating PCM models, requests only influence each other if they compete for the same resources. However, for some applications, such as data stream processing, it is not realistic for requests to be this independent. For example, it is common to group requests in windows over time or to join data streams. Modeling the resulting behavior and resource demands in the system via stochastic approximations is possible but has drawbacks. It requires additional effort for determining the approximation and it may require spreading information across model elements that should be encapsulated in one place. In this paper, we propose a way of modeling interaction between requests that is similar to query languages for data streams. Thus, we introduce state into models without sacrificing the understandability and composability of the model.