1. A computer-implemented method for providing workload windows in a database system having at least one cache fragment, the method comprising: collecting cache-efficiency-indicator values of an at least one cache fragment during operation of a database system over a period of time; providing approximation-function-parameter values for the collected, cache-efficiency-indicator values calculated with an approximation function as exp(c*x) where c is a negative parameter and x is a size of the at least one cache fragment; providing a set of workload windows based on the approximation-function-parameter values; providing workload-window information for the set of workload windows, the workload-window information including at least one approximation-function-parameter value representing each member of the set of workload windows; storing the workload-window information for a comparison based on the collected cache-efficiency-indicator values and the workload-window information; selecting a workload window having first workload-window information matching the approximation function modelling a set of current cache-efficiency-indicator values; and adjusting cache configuration based on the first workload-window information of the selected workload window.