The performance of protocols based on locks with ordered sharing

There is growing evidence that for a wide variety of database workloads and system configurations, locking-based concurrency control outperforms other types of concurrency control strategies. However, in the presence of increased data contention, locking protocols such as two-phase locking perform poorly. In this paper, we analyze a family of locking-based protocols that employ a new relationship between locks called ordered sharing. Using a centralized database simulation model, we demonstrate that these protocols exhibit comparable performance to that of traditional locking-based protocols when data contention is low, and they exhibit superior performance when data contention is high. Furthermore, we show that the performance of these protocols improves as resources become more plentiful. This is particularly significant because the performance of two-phase locking degrades as a result of data contention, not resource contention. Thus, introducing additional resources improves the performance of the proposed protocols, though it does not benefit two-phase locking significantly