PRACTIC: A Concurrent Object Data Model for a Parallel Object-Oriented Database System

N. Bassiliades, I. Vlahavas, “PRACTIC: A Concurrent Object Data Model for a Parallel Object-Oriented Database System”, Information Sciences, Elsevier, Vol. 86 (1-3), pp. 149-178, 1995.

Object-Oriented Databases, Active Objects, Instance Hierarchy, Inheritance, Parallel Method Execution, Vertically Partitioned Systems.

In this paper, a concurrent object data model for a parallel object-oriented database system, named PRACTIC, and its abstract machine are presented. PRACTIC means PaRallel ACTIve Classes and is based on the vertical partitioning and concurrent management of the database schema classes and meta-classes, which are collectively called active objects. Active objects are permanent processes in memory that encapsulate their definitions, methods and management procedures. Semi-active and passive objects exist to realise abstract classes and instances (the actual data), respectively. The object model gives rise to a query/method execution model that provides parallelism on all levels of the instantiation hierarchy. The abstract PRACTIC machine directly maps the model to a MIMD machine. The performance of one of the proposed parallel query/method execution schemes is measured by simulation on the abstract machine.