Processing events in a distributed environment. There is provided an apparatus which includes a central queue for receiving events and tracking their progress through filtering, correlation, and update processing of stateful target objects, at least one filtering node, at least one correlation node and at least one update node. The central queue receives events in their order of arrival, each event having an entry in the central queue. Processing of events is divided into three pipelined stages in the order of filtering, correlating and updating. A result for each event of each of filtering the events, correlating the events and updating the target object is recorded in the central queue as part of the event's queue entry. The method may be performed by one or more computing devices. The exemplary embodiments detect and compensate for any erroneous results due to unsynchronized parallel processing, and guarantee an eventually correct outcome.