Many database systems guarantee the consistency of the database for concurrent transaction processing by a standard locking protocol called two phase locking. The performance of such systems is dependent on various factors, among which are the choices of locking granularity (the amount of data controlled by a single lock) and degree of multiprogramming (the maximum number of transactions allowed to run concurrently in the system). Previous simulation and experimental studies on such systems suggest that the choices are dependent on the properties of the application.