Patent ID: 7979420

Claim:
A method, implemented in a computer, to manage a plurality of streams of data, and a plurality of relations that supply data infrequently relative to said plurality of streams, the method comprising: awakening an operator to process said data, said operator comprising a plurality of inputs; checking if any input in said plurality of inputs of said operator has no data; based on an outcome of said checking finding no data at said any input, said operator processing by assuming receipt from said any input, a null message with a first time stamp, said first time stamp being derived by said computer from a second time stamp of a latest message comprising at least a portion of said data received from another input in said plurality of inputs if at least one predetermined condition is met; and outputting a stream from said computer, a message in said stream being generated in response to a continuous query based at least partially on said operator processing said data using said null message, and multiple messages including said latest message received on multiple inputs other than said any input; wherein said at least one predetermined condition comprises checking whether all inputs, of another operator at said any input, have no data.