Plausible clocks: Constant size logical clocks for Distributed Systems

Abstract

In a Distributed System with N sites, the detection of causal relationships between events can only be done with vector clocks of size N. This gives rise to scalability and efficiency problems for accurate logical clocks. In this paper we propose a class of logical clocks called plausible clocks that can be implemented with a number of components not affected by the size of the system and yet they provide good ordering accuracy. We develop rules to combine plausible clocks to produce more accurate clocks. Several examples of plausible clocks and their combination are presented. Using a simulation model, we evaluate the performance of these clocks.