Relaxed Correctness for Firm Real-Time Databases

Real-time database system must meet time constraints in addition to the integrity constraints. Concurrency control is one of the main issues in the studies of real-time database systems. Traditional concurrency control methods use serializability as the correctness criterion when transactions are executed concurrently. However, strict serializability as the correctness criterion is not always suitable in real-time databases. Instead, correctness requirements vary from one type of transactions to another and from one data type to another. In this paper we propose a concurrency control method witch is based on optimistic methods with a extension to relaxed serializability and semantic conflict resolution so that a special purpose concurrency control scheme can be applied. Proposed method is evaluated and tested in prototype implementation of real-time database system for telecommunications