The demand for scalability in replicated distributed real-time database systems (RDRTDBS) is still explorative and, despite an increase in real-time applications, many challenges and issues remain in designing a more scalable system. The objective is to improve the scalability of the system during system scale up with new replica sites. Existing research has been mainly conducted in maintaining replica consistency between different replicas via replication protocol. However, very little research has been conducted towards improving scalability and maintaining mutual consistency and timeliness. Consequently, the ultimate aim of this chapter is to improve scalability in RDRTDBS such that performance of the system does not degrade even though new replica sites are added.
TopIntroduction
In the current scenario, data is playing a prominent role in many applications and the back-end database system of these application stores such valuable data. This database system requires an efficient and effective management technique (Berrington J., 2007) such that database operation in terms of insertion, deletion, updation, and searching can be processed more easily (Ramakrishnan, R. & Gehrke J., 2000; Ullman, J. D., 1984). Additionally, these database operations can be processed in the centralized manner or distributed manner. The decision to process database operations in the centralized location or distributed location will depend upon the client's requirement (Garcia-Molina H. & Lindsay B., 1990; Bernstein, P. A. et al., 1987). If the application is designed for a small scale, then it is advisable to process database operation in a centralized location. However, if the application is on a large scale, then it is advisable to process database operation in a distributed fashion. Despite this, there are some other factors also that need to be considered such as the number of requests, number of system resources, and so on to quickly decide about the processing location for data operations.
Real time database system (RTDBS) in an emerging area of this database system which is specifically designed to work with real time systems (Aldarmi S. A., 1998) such as space shuttle, flight control system and some others. This database system has a stringent requirement to maintain the timeliness and temporal consistency of the admitted real time transaction (RTT) such that the system can be saved from catastrophic failure (Ulusoy Ö., 1995). As this database system continues to evolve, RTDBS is used in a large number of real time applications and is generating massive amounts of data. Distributed real time database system (DRTDBS) is an extension of RTDBS which is specifically designed to work with such a huge amount of data in a timely manner. The primary objective of DRTDBS is to satisfy the timeliness of the admitted RTT and also to maintain the temporal consistency of real time data items. In the past, large number of researches are conducted in different directions of the DRTDBS such that the performance of the system gets increased. These research directions include concurrency control protocol, buffer management, scheduling RTTs, commit protocol, replication technique and so on (Shanker U. et al., 2008).