The performance of SQL queries to an X.500 directory system

The X.500 standard specifies a distributed directory service designed to store information about people and objects associated with computer networks. Its API is geared towards retrieving information based on this application domain. Recently, a number of projects have used the directory in non-traditional ways. Such applications, however, are constrained by the X.500 information model and the limited functionality of its API. We describe a prototype system that allows users to view the information in a directory as relations, and to query the view using SQL. An analysis of the performance of the system is presented and possible optimizations are discussed. (C) 1998 Elsevier Science B.V.