Patent ID: 8681990

Claim:
A method of managing renewal of a dynamic set of data items in a data item management system, each data item having an associated renewal deadline, the method comprising: maintaining in memory of the data item management system a renewal schedule allocating to each data item in the set a renewal interval for renewal of the data item by the management system; on addition of a new data item to the set, wherein the potential latest possible renewal interval overlaps a time period in the renewal schedule during which the data item management system is busy, applying one of first and second update techniques, and adaptively switching between the first and second update techniques in dependence on a number of data items in the set as the number of data items in the set varies dynamically in time, such that the second update technique is applied when the number exceeds a predetermined threshold; and initiating renewal of each data item automatically on commencement of the renewal interval allocated in the renewal schedule to the new data item; wherein said set of data items is dynamic in that a number of data items in said set of data items varies dynamically in time.