Research On Conflict Problem In Mobile Database Replication Techniques

In recent years with the rapid development of the processing speed of mobile computing devices and wireless communication, the demand for mobile computing is increasing. As an important part of the mobile computing mobile database system has become a hot research field. Distributed computing systems replicate objects on multiple sites to improve both availability and performance. Replication improves availability by letting users access data even when some sites are non-functional. Replication also improves performance by letting users access data from a nearby site. Optimistic replication is essential in mobile database system because mobile devices often disconnect from network. However replication can cause conflicts.In this thesis we first introduce the current situation of research on mobile database replication techniques and conflict problem, then describe optimistic replication and two-tier replication schema in detail and analyze the reasons of conflict problem in mobile database replication techniques. On the basis of above work a mobile database replication solution is designed. This solution focuses on conflict problem in mobile database replication techniques and improves the success ratio of tentative transaction.Finally, we analyze and improve double-timestamp transaction-level synchronization, the result show that the improved model can reduce mobile database transaction log and save space in mobile devices.