Flexible Transaction Management in Advanced Multidatabase Applications

摘要

Advanced applications in autonomous multidatabase need to relax some properties of classical transactions in order to support a flexible processing and to increase the performance of the whole system. In this paper, we define an extended transaction model where a flexible global transaction is a set of subtransactions composed by user to implement a specific task of application, and where subtransactions terminations are not totally dependant. We cope with two major problems of concurrency control in this extended model. The first is related to global transaction commitment. For this purpose, we present an approach allowing the early commit of subtransactions i.e. a subtransaction can commit before global commit decision. The second problem concerns the global deadlock detection and its resolution with respect to the autonomy of local systems and the partial order on subtransactions terminations. For this matter, we establish an effective global deadlock characterization and an efficient potential global deadlock detection algorithm appropriate for multidatabase systems integrating such extended transaction model.