Patent ID: 7904444

Claim:
A computer-implemented method of performing a data stream query, comprising: receiving at a network router the data stream query requiring a join operation on a plurality of data streams, wherein the query requires a join operation involving joining the plurality of data streams using a temporal join condition and computing aggregates of the joined data streams over the temporal grouping granularity; determining whether the join operation can be accurately approximated when the query is received by: comparing the temporal join condition and the temporal grouping granularity of the join operation with integrity constraints of the data streams to determine an error value; and when the error value is less than a threshold value, determining that the join operation can be accurately approximated; generating a plan to approximate results of the received query without performing a join operation by performing independent aggregation operations on each of the plurality of data streams, wherein the independent aggregation operations independently aggregate all values of each of the plurality of data streams over a temporal grouping granularity; and performing the generated plan on the plurality of data streams; and outputting results of the performed plan from the network router as results of the query.