Performance Simulation Performance simulation using queuing model useful to predict bottlenecks as well as the effects of tuning changes,even without access to real system Queuing model as we saw earlier Models activities that go on in parallel Simulation model is quite detailed,but usually omits some low level details Model service time,but disregard details of service E.g.,approximate disk read time by using an average disk read time Experiments can be run on model,and provide an estimate of measures such as average throughput/response time Parameters can be tuned in model and then replicated in real system E.g.,number of disks,memory,algorithms,etc. Database System Concepts-7th Edition 25.11 ©Silberscha乜，Korth and SudarshanDatabase System Concepts - 7 25.11 ©Silberschatz, Korth and Sudarshan th Edition Performance Simulation ▪ Performance simulation using queuing model useful to predict bottlenecks as well as the effects of tuning changes, even without access to real system ▪ Queuing model as we saw earlier • Models activities that go on in parallel ▪ Simulation model is quite detailed, but usually omits some low level details • Model service time, but disregard details of service • E.g., approximate disk read time by using an average disk read time ▪ Experiments can be run on model, and provide an estimate of measures such as average throughput/response time ▪ Parameters can be tuned in model and then replicated in real system • E.g., number of disks, memory, algorithms, etc