Performance evaluation of three logging schemes for a shared-nothing database server

The European Declarative System (EDS) is a high performance backend database server designed for a range of commercial mainframes. One major application domain of EDS is information processing for business and commercial environments. High performance is achieved by exploiting parallelism using a shared-nothing computer (up to 256 processors). Reliability is a crucial design issue for commercial and business information systems. Recovery control facilitates reliability and logging forms an important part of it. In general, logging is costly to implement. It is usually achieved at the expense of reduced system performance. Three logging schemes have been studied for EDS: (a) local discs-adopt a conventional approach by incorporating a local disc on each processor; (b) duplexing-arrange the processors in pairs, one for database operations and one for backup; and (c) cooperative logging-similar to duplexing except database and backup operations are performed on a single processor. The performance of these schemes for on-line transaction processing was evaluated and compared using the EDS behavioural simulator. The results of the evaluations are presented in this paper