Hardware Tuning:Five-Minute Rule Question:which data to keep in memory: If a page is accessed n times per second,keeping it in memory saves n* price-per-disk-drive accesses-per-second-per-disk Cost of keeping page in memory price-per-MB-of-memory ages-per-MB-of-memory Break-even point:value of n for which above costs are equal If accesses are more then saving is greater than cost Solving above equation with current disk and memory prices leads to: 5-minute rule:if a page that is randomly accessed is used more frequently than once in 5 minutes it should be kept in memory (by buying sufficient memory!) Database System Concepts-6th Edition 24.9 @Silberschatz,Korth and SudarshanDatabase System Concepts - 6 24.9 ©Silberschatz, Korth and Sudarshan th Edition Hardware Tuning: Five-Minute Rule Question: which data to keep in memory: If a page is accessed n times per second, keeping it in memory saves  n * price-per-disk-drive accesses-per-second-per-disk Cost of keeping page in memory  price-per-MB-of-memory ages-per-MB-of-memory Break-even point: value of n for which above costs are equal  If accesses are more then saving is greater than cost Solving above equation with current disk and memory prices leads to: 5-minute rule: if a page that is randomly accessed is used more frequently than once in 5 minutes it should be kept in memory  (by buying sufficient memory!)