Analysis of hybrid concurrency control schemes for a high data contention environment

Analytical models are developed to study hybrid CC (concurrency control) schemes which employ a different CC scheme to handle rerun transactions, since their characteristics are different from the first run of transactions. These include switching to static or dynamic locking during rerun (referred to as static and dynamic hybrid OCC (optimistic concurrency control) schemes, respectively), and switching to broadcast OCC during rerun, while doing pure OCC for the first run. In a high data contention environment where locking is inferior to OCC, analysis shows that the performance can be substantially improved by using this hybrid approach and the authors study the tradeoff of the different hybrid CC schemes. The analytic models are based on a decomposition approach and use a mean-value-type analysis. The accuracy of the analysis is validated through simulations