tailieunhanh - Measuring and modelling the performance of a parallel ODMG compliant object database server

A relationship in relational parlance is a table with columns and rows.* A row in the database represents an instance of the relation. Conceptually, you can picture a table as a spreadsheet. Rows in the spreadsheet are analogous to rows in a table, and the spreadsheet columns are analogous to table attributes. The job of the relational data architect is to fit the data for a specific problem domain into this relational model. | CONCURRENCY AND COMPUTATION PRACTICE AND EXPERIENCE Concurrency Computat. Pract. Exper. 2006 18 63-109 Published online 13 September 2005 in Wiley InterScience . DOI Measuring and modelling the performance of a parallel ODMG compliant object database server Sandra de F. Mendes Sampaio1 Norman W. Paton1 1 Jim Smith2 and Paul Watson2 1 Department of Computer Science University of Manchester Oxford Road Manchester M13 9PL . 2Department of Computer Science University of Newcastle uponTyne Newcastle uponTyne NE1 7RU . SUMMARY Object database management systems ODBMSs are now established as the database management technology of choice for a range of challenging data intensive applications. Furthermore the applications associated with object databases typically have stringent performance requirements and some are associated with very large data sets. An important feature for the performance of object databases is the speed at which relationships can be explored. In queries this depends on the effectiveness of different join algorithms into which queries that follow relationships can be compiled. This paper presents a performance evaluation of the Polar parallel object database system focusing in particular on the performance of parallel join algorithms. Polar is a parallel shared-nothing implementation of the Object Database Management Group ODMG standard for object databases. The paper presents an empirical evaluation of queries expressed in the ODMG Query Language OQL as well as a cost model for the parallel algebra that is used to evaluate OQL queries. The cost model is validated against the empirical results for a collection of queries using four different join algorithms one that is value based and three that are pointer based. Copyright 2005 John Wiley Sons Ltd. KEY WORDS object database parallel databases ODMG OQL benchmark cost model 1. INTRODUCTION Applications associated with object databases are demanding in .