Experiences with Building a Federated Transaction Manager based on CORBA OTS

. Federated transaction management is needed to ensure the consistency of data that is distributed across multiple, largely autonomous, and possibly heterogeneous component databases and accessed by both global and local transactions. The problem of how to achieve global serializability has been intensively studied in the literature, but none of the proposed approaches can be considered as a universally 'best' strategy. Rather a federated transaction manager should support a suite of strategies and allow selecting the most suitable protocol for each application. Furthermore, it should not only concentrate on the idealized correctness criterion of serializability, but also oer support for dierent isolation levels, which are widely used in existing database systems. This paper presents the design and implementation of a CORBA-based customizable transaction manager for a federate database system. It gives a discussion of how OTS, the CORBA approach to distributed transactions, can be us..