Performance analysis of optimistic concurrency control schemes with different rerun policies

The pure optimistic concurrency control (OCC) scheme, which only aborts a transaction at its commit time, can do better than aborting transactions as soon as conflict is detected (broadcast OCC). To further exploit this phenomenon, hybrid CC schemes are devised which use a different CC scheme to handle rerun transactions. These include switching to static or dynamic locking (static and dynamic hybrid OCC schemes, respectively) or to broadcast OCC during rerun, while doing pure OCC for the first run. In the high-data contention environment, where locking is inferior to OCC, it is found that the static and dynamic hybrid OCC can do better than OCC