An optimistic multi-level concurrency control for nested typed objects

The authors present a transaction model adapted to an object-oriented environment and capable of taking the semantics of objects and operations into account. They also describe a multilevel concurrency control fitted to this model. The main advantage, compared to locking methods, of this optimistic method which uses timestamps intervals is that it exploits conditional commutativity, depending upon return values. Therefore, it is particularly well suited to situations where this kind of commutativity is frequent, especially when operations last long. Nevertheless, like any optimistic method, it is efficient only if conflicts are rare. In the cases where conflicts are frequent but essentially caused by some well-identified operations, a possible approach would be to consider letting the method coexist, at any level, with a method using typed locks (mixed concurrency control)