On the Need for Extended Transactional Models@Run.Time.

Models at runtime that are causally connected to the base software play a central role in the software architecture of flexible and self-adaptive software systems. Decisions based on them may be wrong if the models are accessed or modified in a state different than assumed. Although transaction concepts for model repositories have been presented in analogy to well-established transaction concepts for databases, they do not sufficiently address the specific needs for models at runtime. In this paper, we describe some of the extended features expected from a runtime environment for Transactional Models@Run.Time (TMRT). These features are derived from issues identified in the context of the Graph-based Runtime Adaptation Framework (GRAF).