At the PASS Summit in Seattle, one of the outstanding keynote presentations was by Dr. Dave DeWitt, Microsoft Fellow, and leader of the Microsoft Jim Gray Systems Lab, in Madison, WI.
Dr. DeWitt is working on releases 1 and 2 of SQL Server Parallel Database Warehouse. In his keynote he reviewed the 30 year history of CPU, memory, and disk performance. Variations in performance gains across these subsystems, with disk performance lagging badly, have major impacts on database system performance.
Disk performance gains have been made in three areas, Capacity, Transfer Rate, and Average Seek Time. However, the gains over the last 30 years have not been uniform.
Capacity of high performance disk drives has increased by a factor of 10,000. Transfer rates have increased by a factor of 65. The average seek time has only increased by a factor of 10. Dr. DeWitt talked about the impact of these discrepancies on OLTP and Data Warehouse applications.
One of his conclusions is that some problems can be fixed through smarter software, but that “SSDs provide the only real help.”