While commit protocol variants (i.e., PA, PC, IBM-PN, PrN, EP, CL, etc.) provide certain efficiencies, when forced in cooperation for the commitment of a distributed transaction in heterogeneous systems, problems and incompatibilities arise. These incompatibilities appear because of the differences in the commit protocol variants each one of the participants uses. Even if the different participants support the same commit variant, problems might again exist if these variants support different commit optimizations. Work in the first three following publications represents the first ever effort in integrating commit protocols. Specifically, the first two, describe the integration of PA and IBM-PN since these are the dominant commit protocols in use. The resulted protocol, called generalized presumed abort (GPA), has already being implemented in IBM's DB2 V.4, AS400 and CICS.

In our recent work we studied how the different commit protocol variants, enhanced with optimizations or not, can coexist in the form of a universal commit protocol that allows the execution of distributed transactions in heterogeneous systems. This universal commit protocols is called "All Two-phase Commit" (ALL2PC). This work resulted in a BS thesis (the last publication below) at the University of Cyprus and is in preparation for conference and journal publication.

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