The task of an information integration system is to combine data residing at different sources, providing the user with a unified view of them, called global schema. Users formulate queries over the global schema, and the system suitably queries the sources, providing an answer to the user, who is not obliged to have any information about the sources. Recent developments in IT such as the expansion of the Internet and the World Wide Web, have made available to users a huge number of information sources, generally autonomous, heterogeneous and widely distributed: as a consequence, information integration has emerged as a crucial issue in many application domains, e.g., distributed databases, cooperative information systems, data warehousing, or on-demand computing. Recent estimates view information integration to be a $10 Billion market by 2006 [14].

The database analyzer and predictor (DBAP) is a CASE (computer-aided software engineering) tool supporting the design and tuning of IDMS (integrated data-management system) DB/DC applications. It is an interactive system, completely integrated with the IDMS online environment and providing the database designer with a comprehensive set of performance analysis models evaluating principal aspects of the database system performance. Close coupling of the workload analysis models with the computer system model provides a means for predicting the response-time behavior of the modeled database system. The performance-oriented database methodology, supported by a menu-driven user interface, guides the users through the database design, as well as existing database system tuning and capacity-planning projects.>

General architecture of a transaction workload analyzer for the Codasyl DBMS environment is presented. The proposed solution is discussed in the framework of general performance problems typical for a Codasyl database environment. Major functions of the Workload Analyzer such as the data manipulation algorithm analysis, the DML statement expansion and the cost model underlying the workload evaluation are described.