Abstract: Optimizing window joins over data streams can include receiving an input topology and calculating costs of computing a join of data streams based on a number of model topologies, and determining an optimal topology based on the calculated costs and the input topology, wherein the input topology, the model topologies, and the optimal topology each include a number of interconnected operators.

Abstract: Optimizing window joins over data streams can include receiving an input topology and calculating costs of computing a join of data streams based on a number of model topologies, and determining an optimal topology based on the calculated costs and the input topology, wherein the input topology, the model topologies, and the optimal topology each include a number of interconnected operators.

Abstract: A method of evaluating nested complex sequence pattern queries includes obtaining events from an event stream and evaluating the events within a first window using an outer query to produce outer partial results. The method also includes determining a more stringent window constraint, the more stringent window constraint comprising a subset of the window constraint corresponding to events that produces the outer partial results and passing the more stringent window constraint to an inner query nested within the outer query. A complex event processing system is also provided.

Abstract: A method of evaluating nested complex sequence pattern queries includes obtaining events from an event stream and evaluating the events within a first window using an outer query to produce outer partial results. The method also includes determining a more stringent window constraint, the more stringent window constraint comprising a subset of the window constraint corresponding to events that produces the outer partial results and passing the more stringent window constraint to an inner query nested within the outer query. A complex event processing system is also provided.