Abstract
This paper describes results of a simulation model for decomposition of concurrency control enforcement in databases. The database is partitioned into atomic data sets using constraints defined during database design. For each atomic data set A, the transaction writer declares a point in his transaction after which there will be no more accesses to A. This location is a candidate for early commitment. We present three new concurrency control protocols: early-commit versions of conventional locking, timestamp ordering, and optimistic protocols, and two new recovery protocols: merged-commit and replay. A simulation model used to model these protocols is described. The new protocols performance is compared to that of their conventional counterparts using the described simulator.