Complex and data-intensive database queries mandate parallel processing strategies
to achieve sufficiently short response times. In praxis, parallel database processing is mostly based on so-called "shared nothing" architectures entailing a physical partitioning and allocation of the database among multiple processing nodes. We examine the performance of such architectures by using a detailed simulation system. We analyse response time performance of transactions and individual database queries in single-user as well as in multi-user mode. Furthermore, we study the throughput behavior for on-line transactions. Three workload types covering a wide range of commercial applications are used for performance evaluation: the debit-credit benchmark load, synthetically generated relational queries as well as real-life workloads represented by database traces.