US Patent 9171037 Searching for associated events in log data

To retrieve a sequence of associated events in log data, a request expression is parsed to retrieve types of dependencies between events which are searched, and the constraints (e.g., keywords) which characterize each event. Based on the parsing results, query components can be formed, expressing the constraints for individual events and interrelations (e.g., time spans) between events. A resultant span query comprising the query components can then be run against an index of events, which encodes a mutual location of associated events in storage.