Delay-Aware Mobile Transactions

In the expanding e-society, mobile embedded systems are increasingly used to support transactions such as for banking, stock or database applications. Such systems entail a range of heterogeneous entities - both the embedded devices and the networks connecting them. While these systems are exposed to frequent and varied perturbations, the support of atomic distributed transactions is still a fundamental requirement to achieve consistent decisions. Guaranteeing atomicity and high performance in traditional fixed wired networks is based on the assumption that faults like node and link failures occur rarely. This assumption is not supported in current and future mobile embedded systems where the heterogeneity and mobility often result in link and node failures as a dominant operational scenario. In order to continue guaranteeing strict atomicity while providing for high efficiency (low resource blocking time and message overhead) and acceptable commit rate, transactional fault-tolerance techniques need to be revisited perhaps at the cost of transaction execution time. In this paper, a comprehensive classification of perturbations and their impact on the design of mobile transactions is provided. In particular we argue for the delay-awareness of mobile transactions to allow for the fault-tolerance mechanisms to ensure resilience to the various and frequent perturbations.