3. The method of claim 2, the predefined expiration criteria comprising presence of a dataset entry in the dataset access log for a predetermined time without that dataset being accessed.
3. The method of claim 2, the predefined expiration criteria comprising presence of a dataset entry in the dataset access log for a predetermined time without that dataset being accessed. 4. The method of claim 3, in the case of event triggers caused by access of the cached dataset, the training output comprising a ratio between (1) the predetermined time reduced by an amount of time between the training time and the trigger time and (2) the predetermined time.