¡¡Chinese Journal of Computers   Full Text
  TitleHypo-Serializable Concurrency Control in Parallel Broadcast Environments
  AuthorsDANG De-Peng
  Address(College of Information Science & Technology, Beijing Normal University, Beijing 100875)
  Year2008
  IssueNo.3(450¡ª455)
  Abstract &
  Background 		Abstract Serializable concurrency control protocols are inapplicable in mobile broadcast environments due to a number of constraints of wireless communications and characteristics of mobile real time applications. In this paper, the use of hypo-serializability for mobile parallel broadcast environments is proposed. At first, hypo-serializability is formally defined. Next, it is proved that hypo-serializability is more relaxing than traditional serializability while consistency is maintained all the time. Then, the necessary and sufficient conditions for hypo-serializability are shown. Furthermore, the parallel hypo-serializable concurrency control protocol BCC-HSR is proposed. Finally, through a series of simulation studies, it is confirmed that the proposed protocol could improve average response time of mobile transactions significantly.

keywords database systems; mobile database; mobile transaction; concurrency control; parallel data broadcast

background Research on the problem of data consistency in mobile broadcast systems is very important. Most of recent studies that have focused on transaction processing in the asymmetric broadcast environments only support read only transactions at the mobile clients. Some methods that support update transactions have been provided. However, they are based on serializability that is too strict to support many mobile applications. Previous relaxing serializability such as epsilon and similarity serializability would sacrifice database consistency to some extent. This paper focuses on consistent and relaxing concurrency control for parallel broadcast systems, and the proposed protocol BCC-HSR supports both read only transactions and update transactions, always maintains data consistency and can improve average response time of mobile transactions significantly.
This research is sponsored by National Science and Technology Support Plan Foundation of China under contract number 2006BAK01A07£¬Chinese Post-doctor Science Foundation under contract number 2003034146, National Natural Science Foundation of China under contract number 60573094.