Transaction Commitment at Minimal Communication Cost

We consider the communication protocol for transaction commitment in a distributed database. Specifically, the connection between the structure of communication among the participating sites, and the communication network topology is investigated. In order to do so, the cost of transaction commitment is defined as the number of network hops that messages of the protocol must traverse. We establish the necessary cost for transaction commitment, and show that it is also sufficient. A simple distributed algorithm is presented to prove sufficiency. Our algorithm is also time-efficient, and in order to prove that we show that the timing of our algorithm is optimal within a natural class of commit-protocols.