1. A computer program product, comprising: a non-transitory computer readable storage medium comprising computer readable program code embodied in the medium that when executed by a processor of an application analysis computer causes the processor to perform operations comprising: obtaining from user terminals, reports containing performance metrics for applications processed by user terminals and characteristic dimensions having values characterizing the applications and the user terminals; generating a statistic separately for each different type of the performance metrics across the reports; identifying one of the statistics, for one type of the performance metrics, that has changed at least a threshold amount between two time intervals; selecting the one type of the performance metrics for analysis; for each combination of a different type of the characteristic dimensions and a different value among the values occurring for the type of the characteristic dimension, generating a statistic for the selected type of the performance metrics from the reports, within a time interval, having the combination of the type of the characteristic dimension and the value, and incrementing a counter that tracks a number of occurrences of the combination of the type of the characteristic dimension and the value among the reports; identifying one of the statistics, for the selected type of the performance metrics from the reports within the time interval having the combination of the type of the characteristic dimension and the value, that has changed at least a threshold amount between the time interval and a previous time interval; searching a list of active warning IDs to identify one of the active warning IDs associated with the combination of the type of the characteristic dimension and the value for the identified statistic; and communicating information based on the identified one of the active warning IDs.