A Real Time Optimistic Strategy to achieve Concurrency Control in Mobile Environments Using On-demand Multicasting

Abstract

In mobile database environments, multiple users may access similar data items irrespective of their physical location leading to concurrent access anomalies. As disconnections and mobility are the common characteristics in mobile environment, performing concurrent access to a particular data item leads to inconsistency. Most of the approaches use locking mechanisms to achieve concurrency control. However this leads to increase in blocking and abort rate. In this paper an optimistic concurrency control strategy using on-demand multicasting is proposed for mobile database environments which guarantees consistency and introduces application-specific conflict detection and resolution strategies. The simulation results specify increase in system throughput by reducing the transaction abort rates as compared to the other optimistic strategies proposed in literature.

Lock-free hybrid concurrency control strategy for mobile environment

“…Thus, aborting transaction at this stage especially in long live transaction decreases system performance by aborting many transactions. To remedy this, [4] presents a strategy, which uses an on-demand multicasting thereby minimizing the number of aborted transactions. However, this strategy is associated with unnecessary transaction restart.…”

“…Several works [1,3,[4][5][6][7][8] implemented the concurrency control strategies in mobile environment but because of the complexities of the issues to be considered such as mobility, low-bandwidth, frequent disconnection, low battery etc., most of the approaches were characterized by problems like deadlock, starvation, time lag between local and global commit, higher rate of abort, unnecessary restart.…”

A Concurrency Control Method Based on Commitment Ordering in Mobile Databases

“…In reference [12] optimistic method is utilized. At the time of completion of transactions, updated data are sent to other mobile transactions using these data.…”

Commit Protocols in Mobile Environments: Design & Implementation

“…Pessimistic commit protocols suitable for mobile environments are presented from [5] to [8]. Further a Real Time optimistic Commit protocols with a conflict resolution strategy is presented in [9]. The Design & Implementation of Pessimistic Commit protocols is described in [10].…”

“…In optimistic concurrency control strategy, the data items are not locked and can be used by more than one mobile host at the same time. The transaction executes in two phases: In the first phase the transaction is committed locally on mobile host using the on-demand approach [9]. In the second phase the results are updated onto the fixed host.…”