A description is given of a detailed simulation study of the performance of multiversion database systems. The characteristics and the extent to which they provide performance benefits over their single-version counterparts are investigated. First, the structure of a software prototyping environment for the evaluation of distributed database systems is presented. Using this environment, the authors shows that for specific workloads, multiversion database systems offer performance improvements despite additional CPU and I/O costs involved in accessing old versions of data. It is also shown that transaction size is one of the most critical parameters affecting the system performance.>