Forgot your password?
Document Actions
How is TIMERON calculated and what is it ?
The timeron value is meant to convey the relative cost of the search for the query
- A timeron is a cost estimate calculated by DB2 based on an evaluation of the resources that will be used. IBM uses a proprietary algorithm for calculating timeron values that estimates the total cost as a weighted sum of the I/O cost and processor cost.
- A weighting factor is applied to both the I/O cost estimate and CPU cost estimate to apply more (or less) emphasis to I/O versus CPU. So, if I/O were given a weighting factor of 1 and CPU given a weighting factor of 0.5, CPU cost would be weighted at half of the I/O cost. Actually, this weighting factor is the default used by DB2.
- To determine the appropriate emphasis, DB2 examines the CPU model being used. Based upon this value, specific weighting factors are applied. Of course, the DB2 optimizer will utilize the statistics, indexes, filter factors, and other information at its disposal to estimate I/O and CPU cost (before applying the weighting factors).
Source: http://www-1.ibm.com/support/docview.wss?uid=swg21207055
Hacker Rangers - Gamification for CyberSecurity