Load shedding for sliding window aggregation queries over data streams

Aggregation queries with sliding window are widely used in data stream management system. Load shedding must be taken into account as data stream burst into the aggregation queries. This paper analyzed characteristics of subset model and deficiencies of current load shedding methods. Gave restrictions of the load shedding problem,and a load shedding algorithm based on the strategy of drop window update. It could guarantee the produce of subset result. The theoretical analysis and experiments show that the algorithm is effective and efficient for the load shedding of aggregation queries over data streams.