Data Freshness Guarantee and Scheduling of Update Transactions in RTMDBS

The demand on mobile and real-time database application and service is becoming increasingly extensive, since the workload cannot be precisely predicted so that they can become overloaded possibly. Many update transactions often missed their deadline because of competing for the limited system resources severely, so data freshness could not be guaranteed in RTMDBS (mobile and real-time database systems). In this paper, a novel performance metric and data freshness in value domain are proposed for example deadline miss ratio of transactions based on data relationship in the directed acyclic graph to ensure the quality of service in mobile and real-time database systems. Feedback control architecture is proposed in our system to decrease miss ratio of transactions and improve data freshness. The scheduling algorithm can guarantee data freshness in time and value domain through simulation experiments.