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Performance Analysis of Concurrency Control Mechanisms for OLTP Databases

—Concurrency control (CC) in distributed and multidimensional databases is becoming more important due to recent increase in high-volume data storage with increasing online transaction processing (OLTP) requirements for medium and large organisations. This paper examines three concurrency control mechanisms commonly adopted and analyses their performance in distributed databases for OLTP operational systems of enterprises. The three CC mechanisms investigated are, two phase locking (2PL), wait depth limited (WDL) and optimistic concurrency control. These CC mechanisms have been studied well in disk-based systems. However, with the recent advances of cost-effective main memory or in-memory storage that can support much higher transaction rates than disk-based systems, there is sufficient motivation to re-investigate the performance of such CC mechanisms in diverse processor configurations. This paper presents a comparison of their behaviour and performance in terms of throughput rates achieved with varying transaction size and contention. The outcome of this study has resulted in further research proposals for improving the performance of these CC mechanisms for OLTP databases.