Integration processes are increasingly used in order to integrate distributed and heterogeneous systems. Although transactional behavior of workflows has been discussed extensively, recovery processing has been disregarded so far. Due to the huge number of different integration systems and models, there are also different transaction concepts with overlapping functionalities available. However, there is the need for a discussion of problem categories and guarantees in order to consolidate the existing transaction concepts. In this paper, we survey possible anomalies of recovery processing in message-oriented middleware and--in conclusion--we define the comprehensive transaction model SIR for data-intensive--but instance-based--integration processes. This model includes the definition of specific transaction levels, which are the precondition for the integration process optimization under transactional restrictions.