Horizontal fragmentation in object DBMS: new issues and performance evaluation

Horizontal fragmentation may improve the performance of database systems. Defining primary and derived horizontal fragmentation along the classes in a database schema is an important and complex issue, yet not discussed in the literature, which must be considered when horizontally fragmenting a database. In this paper, we focus on an analysis to help the designer upon the decision for primary or derived horizontal fragmentation. This analysis considers performance results of distributed databases using horizontal fragmentation to evaluate the potential benefits and drawbacks of primary and derived techniques. Therefore, this paper presents a horizontal fragmentation algorithm that chooses the most adequate strategy (primary or derived) based on class relationships, single class access and query access frequencies.