A queueing network model of Oracle Parallel Server

An approach to modelling an Oracle database is presented for both single instance and parallel server versions. A modified queueing network is used which is extended to include traditional transaction locks which achieve serialisation and the new PCM locks of Oracle which ensure coherency in the distributed database buffers. The latter are not enqueue locks and so require different techniques. Both locks require an iterative solution to a fixed point model. The numerical results produced by the model can be validated largely using data maintained in Oracle tables and the distributed lock manager, and we identify the relevant entries.