Two-phase commit optimizations in a commercial distributed environment

Abstract

An atomic commit protocol can ensure that all participants in a distributed transaction reach consistent states, whether or not system or network failures occur. The atomic commit protocol used in industry and academia is the well-known two-phase commit (2PC) protocol, which has been the subject of considerable work and technical literature for some years. Much of the literature focuses on improving performance in failure cases by providing a non-blocking 2PC that streamlines recovery processing at the expense of extra processing in the normal case. We focus on improving performance in the normal case based on two assumptions: first, that networks and systems are becoming increasingly reliable, and second, that the need to support high-volume transactions requires a streamlined protocol for the normal case. In this paper, various optimizations are presented and analyzed in terms of reliability, savings in log writes and network traffic, and reduction in resource lock time. The paper's unique contributions include the description of some optimizations not described elsewhere in the literature and a systematic comparison of the optimizations and the environments where they cause the most benefit. Furthermore, it analyzes the feasibility and performance of several optimization combinations, identifying situations where they are effective. © 1995 Kluwer Academic Publishers.