Incompatibility Dimensions and Integration of Atomic Commit Protocols

Yousef Al-Houmaily
Department of Computer and Information Programs, Institute of Public Administration, Saudi Arabia

Abstract: Advanced software application systems contain transactions that tend to traverse incompatible database sites belonging to different human organizations. One key requirement of these application systems is universal transactional support and, in particular, guaranteeing the atomicity property of transactions in the presence of incompatible atomic commit protocols. Detailed analysis show that incompatibilities among atomic commit protocols could be due to the semantics of coordination messages or the presumptions about the outcome of terminated transactions. This leads to the definition of “operational correctness”, a criterion that captures the practical integration of incompatible atomic commit protocols. It also leads to the definition of “safe state”, a notion that determines the conditions under which all information pertaining to distributed transactions can be discarded without sacrificing their consistent termination across all participating sites. The significance of the analytical results is demonstrated through the development of a new atomic commit protocol called “integrated two-phase commit” that integrates the most commonly known atomic commit protocols, with respect to applicability and performance, in a practical manner and in spite of their incompatibilities.

Keywords: Two-phase commit, voting protocols, distributed transaction processing, integrated database systems, internet transactions, electronic services and electronic commerce.

Received March 26, 2007; accepted June 9, 2007