Typical tuning and database performance activities are often based on ratios and sometimes they give misleading results. As database functionality continues to become more sophisticated, new methods of tuning will become more useful.
An example of this is the Wait-Time information in Microsoft SQL Server. This allows tracking of every step of a process so you can identify which steps are causing a lag in performance.
Consider the metaphor of the cashier in relation to performance tuning:
The Cashier is the CPU
Customer Being Checked is Running
Customers Waiting in Line are Runnable
Customer 1 Requires a Price Check
Price Check is Runnable
If you use a ratio or a simple statistic such as total time at a cashier, you may end up taking the wrong action to fix the problem.
Wait-time analysis would give you a clearer picture, by isolating the ...