Stamp locking method for multiversion composite objects

Abstract

In this paper a new approach to locking multiversion composite objects is proposed, called the stamp locking approach. The main notion of this approach is a stamp lock defined as an extension of a classical lock in such a way that it contains the information about the position of locked nodes in the hierarchies concerned. The main advantage of this method is simple locking strategy following from the lack of intentional locks. To lock a hierarchy subtree it is sufficient to set one stamp lock only, whose node stamp identifies the subtree root. To determine stamp lock compatibility, it is sufficient to compare stamps that are particular identifiers of hierarchy nodes and subtrees. Advantages of the stamp locking method become particularly beneficial in the case of a database containing many versions of composite objects, whose composition structure is complex. This is a typical case of design databases where objects, being the artifacts of the design process, have usually many components available in many versions.