International Journal of Database Theory and Application Vol.8, No.1 (2015), pp.205-212 http://dx.doi.org/10.14257/ijdta.2015.8.1.21 ISSN: 2005-4270 IJDTA Copyright ⓒ 2015 SERSC A Heuristic approach for Effective Management of Concurrent Transactions in Mobile Environments Salman Abdul Moiz School of Computer & Information Sciences, University of Hyderabad Salman.abdul.moiz@gmail.com Abstract The inherent limitations of mobile environments like disconnections, mobility, bandwidth etc affects the performance of system when several mobile clients access the shared data items at the same time. Several timeout based strategies are implemented in literature to deal with the starvation of data items during disconnections and mobility. This increases the abort and rollback rates. In the proposed heuristic approach, the time for execution of a transaction can be predicted based on the given timer value for a specific mobile client. The simulation results show the time for execution can be dynamically estimated given the timer value and vice versa for a particular request originating from specific mobile clients. This increases the throughput of the system as compared to the timer based strategies proposed in the literature. Keywords: Concurrency, mobile clients, heuristics, timer, time for execution 1. Introduction When multiple mobile clients access the shared data items simultaneously it leads to data conflicts resulting in inconsistency of data items. Due to distributed nature of mobile transactions and the inherent limitations in processing of transactions on move makes concurrency control a challenging problem. Traditionally concurrency is guaranteed by locking the shared data items. However due to disconnections and mobility, it may lead to starvation of shared resources. The timer based strategies addressed this problem. However this decreases the throughput of the system. In this paper a heuristic approach is proposed which evaluates the time for execution of a transaction based on the given timer value for specific mobile clients. The intuition is that the time taken for executing a transaction differs from one mobile client to the other. Further for a specified timer value by the service provider the proposed strategy can evaluate the time taken to execute the transaction using regression analysis. The simulation results show better throughput in addition to increase in commit rate of the transactions. The paper is organized as follows: Section -2 describes the related work; Section -3 presents the architecture of mobile database system. Section-4 presents the heuristic approach that estimates the expected time for execution for a given timer value & mobile client. Section -5 presents the simulated results and Section -6 concludes the paper. 2. Related Work When multiple mobile hosts access the same date items simultaneously then it may lead to data inconsistency. One of the primary problems in mobile data base environment is Data Conflict anomaly [1]. Optimistic concurrency control techniques are proposed to resolve the data conflict in transaction validation phase. However it may lead to delay in responding to the request. Two phase locking protocol [2] guarantees serializability in