Design and Implementation of an Efficient, Reliable and Safe Work-Package Database System at CERN

Abstract

The Activity Coordination Tool (ACT) is a web application designed to automate theplanning and coordination of work packages. In the CMS experiment at CERN it isimportant that work packages in the underground facilities are properly planned inorder to not jeopardize time schedules, equipments, budgets and safety. The subjectof this thesis is the development of the database schema used by the ACT application.The schema has been developed from scratch in order to best fit the needs of CMS andto cover all aspects of the planning and coordination process not found in other CERNdatabases.Models and diagrams of the database schema are based on a step by step descriptionof the work package process. This step by step description was used to organize thedata, to make the data and data relationships consistency, and to make the databasestructure flexible for extensions in the future. These models would eventually be usedto implement the schema in the CMS online database.Another database at CERN has many similarities with the ACT database. These twodatabases will eventually merge due to common interest, and the ACT database schemaneeded therefore to resemble some tables in this database in order to facilitate themerging. Some problems with network traversal and security needs to be solved beforethese two databases can be merged.The architecture and usage of the database schema can affect the database performancebut it doesn t contribute to the reliability of the databases system. The hardware andsoftware components making up the database system itself are usually the main contributorsto this. The CMS online network work hard to keep the performance and reliabilityof their database system as good as possible. Everything from disks to networkconnections is redundant. In addition to component redundancy are features providedby Oracle used to improve performance. The amount of server redundancy does howeverseem a bit exaggerated, and the performance could be slightly improved if otherOracle features were used.