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This thesis is concerned with the design and im plementation of a Relational Multimedia Database System, in short RMDBS. RMDBS is designed to efficiently use storage space and manipulate various kinds of data; attribute data, bit-m apped pictures, and program s in binary code. RMDBS is an integrated system which enables the user to manage and control operations on the different forms of data in a user friendly manner. This means that even nonexperienced users can work with the system. The work described in this thesis is novel in that a true multimedia database has been implemented within the framework of a traditional relational DBMS. Previous work in this area has concentrated either in building data base management systems for storing picture-based data or multimedia databases which are not true data base management systems. RMDBS is implemented using the Revelation data base management system.

Thesis (Ph. D.)--University of Queensland, 2002. / Includes bibliographical references.

Preci* is a generalised distributed database management system, capable of supporting heterogeneous, pre-existing databases as nodes. The system is fully decentralised, supporting both retrieval and update of the data. Varying degrees of location transparency can be provided, according to user requirements. The work presented here is concerned with data integration and query decomposition. An extended relational algebra (PAL) is developed, which serves both as a query language and as a mapping language for data integration. The suitability of PAL for data integration is demonstrated by a number of examples, and by comparison with existing proposals. A major attraction of PAL is that it can also be used as a query language, thereby making query decomposition much easier. The relational algebraic approach is shown to be particularly appropriate for query decomposition, since queries can be easily parsed and represented in tree form. Such parse trees are readily transformed to yield equivalent expressions which will execute more efficiently. An algorithm is given for decomposing global PAL queries into nodal subqueries, and for coordinating their execution. The general problem of allocating subqueries to execution nodes is not tackled, though it is shown that the algorithm will do this allocation under specific implementation conditions. A prototype of Preci* has been implemented in 'C'.

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Resource allocation in a database management system (DBMS) is a performance management process in which an autonomic DBMS makes resource allocation decisions based on properties like workload business importance. We propose the use of economic models in a DBMS to guide the resource allocation decisions. An economic model is described in terms of business trades and concepts, and it has been successfully applied in some computer system resource allocation problems. In this thesis, we present approaches that use economic models to allocate single and multiple DBMS resources, such as main memory buffer pool space and system CPU shares, to workloads running concurrently on a DBMS based on the workloads’ business importance policies. We first illustrate how economic models can be used to allocate single DBMS resources, namely system CPU shares, to competing workloads on a DBMS. We then extend this approach to using economic models to simultaneously allocate multiple DBMS resources, namely buffer pool memory space and system CPU shares, to competing workloads on a DBMS based on the workload business importance policy in order to achieve their service level agreements. Experiments are conducted using IBM® DB2® databases to verify the effectiveness of our approach. / Thesis (Master, Computing) -- Queen's University, 2008-11-17 15:35:50.303

Database Management Systems (DBMSs) are an integral part of many applications. Web-based applications, such as e-commerce sites, are faced with highly variable workloads. The number of customers browsing and purchasing items varies throughout the day and business managers can further complicate the workload by requesting complex reports on sales data. This means the load on a database system can fluctuate dramatically with a sudden influx of requests or a request involving a complex query. If there are too many requests operating in the DBMS concurrently, then resources are strained and performance drops. To keep the DBMS’s performance consistent across varying loads, a load control system can be used. This thesis investigates the concept of a load control system based on regulating individual resource usage in a predictive manner. For the purpose of this proof-of- concept study, we focus on a specific resource; namely, the sort heap. A method of estimating sort heap usage based on the query execution plan is presented and several scheduling methods based on these estimations are proposed. A prototype load control system is used to evaluate and compare the scheduling methods. Experiments show that it is possible to both estimate sort heap requirements and to control sort heap usage using our load control system. / Thesis (Master, Computing) -- Queen's University, 2011-06-09 11:02:31.595