1. A system for discovering bugs, comprising: a memory coupled to a processor, and configured to provide the processor with instructions for execution of: an input interface configured to receive an event log, wherein the event log comprises a text file of software status messages; the processor further configured to: parse the event log to build an event symptom database, wherein the event symptom database comprises a structured database of software status messages; evaluate a bug definition on the event symptom database by executing a composable bug query expression that includes at least one of an event, an interval algebra operator, or a time constraint to express bug patterns that are indicated by one or more events with time interval information, and to determine whether a bug as defined by the bug definition has occurred, wherein the bug definition comprises a set of rules for identifying bugs, wherein a rule for identifying bugs comprises an event symptom condition; and provide a list of bug occurrences.