Non-uniformly shared access to a database: A probabilistic approach on modelisation

The study of transaction processing systems providing access to a database involves the taking into account of control policies for concurrent accesses. The influence of locking mechanisms on the behaviour of those systems is all the more important that, in practice, proceeding of access to the base are not uniformly shared on the whole locking units. Generally, one part of the database is more often accessed than the others. The authors have attempted to solve this problem through a probabilistic analysis intermixed with a hierarchical analytical modelling. The numerical results show the influence produced on the performance of system by the localization of accesses to the database.