PRACTIC - A CONCURRENT OBJECT DATA MODEL FOR A PARALLEL OBJECT-ORIENTED DATABASE SYSTEM

摘要

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 arid concurrent management of the database schema classes and metaclasses, which are collectively called active objects. Active objects are permanent processes in memory that encapsulate their definitions, methods, and management procedures. Semiactive and passive objects exist to realize 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. [References: 26]