Performance studies of concurrency control in distributed real-time database systems on ATM networks

In recent years, different efficient real-time concurrency control protocols for distributed real-time database systems (DRTDBS) have been proposed and their performance have been examined with the use of a simulation model. Although the performance of the underlying network should have a significant role, or even a deterministic role, on the overall system performance, the network issues in their studies are always being neglected. In nearly all these studies, they are modeled as simple constant delay servers and it is always assumed that the same delay is applied to all types of messages in the systems. It is the objective of this paper to investigate the possible impact of different network assumptions on the performance of concurrency control protocols in DRTDBS. The results show that the unpredictable behavior of the underlying network will give non-constant network transit time which in turn cause impact to the performance of concurrency control protocols.