Abstract: To help a database administrator assess the impact of database server changes on applications, trace files are preprocessed into intermediate files with events sorted by generation order. Unused event classes and columns of a trace file are excluded, and pre-calculated data may be included. Intermediate files are then dispatched across a set of clients, and replay occurs in a synchronization mode or a stress mode. Synchronization mode releases events in submission order, whereas stress mode releases events in emulation of their original timing. Replay parameters include server idle time cap, query timeout value, a connect-time scaling factor for scaling time between trace start and connection login, and a think-time scaling factor for scaling the time between events on a replay client—database server connection. Each replay client generates a result file, which a replay controller aggregates for administrator analysis.