A Performance Evaluation of OID Mapping Techniques
André Eickler, Carsten A. Gerlhof, Donald Kossmann · 1995
In this paper, three techniques to implement logical OIDs are thoroughly evaluated: hashing, B-trees and a technique called direct mapping. Among these three techniques, direct mapping is the most robust; it induces at most one page fault to map an OID, and it scales very well to large, rapidly growing databases. Furthermore, the clustering of handles that are used to map logical OIDs is studied. In particular, the performance of B-trees and direct mapping can improve significantly if the handles of objects that are frequently accessed by the same methods are clustered. For direct mapping, two placement policies are compared: linear and matrix clustering. 1 Introduction The full support of object identity is one of the most important features of object-oriented database systems [KM94]. To improve referential integrity, an object base system allocates an object identifier (OID) to every object at the time the object is created. The OID is used to identify the object uniquely and to im...