Design And Implement Of Top-k Query In P2P Network

In recent years, with the rapid development of the information technology, information resources have been greatly enriched. How to retrieve the small amount of the most valuable information from the massive data in P2P network quickly has become a great challenge for the database field. Top-k queries based on ranking elements stop query processing when the top-k ranked results can be safely determined including aggregate top-k query and non-aggregate top-k query. Given an aggregate operation, a top-k query is to find the k objects with the highest (or the lowest) aggregate values. Existing top-k aggregate query algorithm has the uniform threshold and selects the object according to the value standard neglecting the data distribution. The existing non-aggregation top-k algorithm only supports peer pruning search, and users can not search the data based on pruning the illegal object.This paper proposes hybrid non-uniform threshold algorithm in P2P network, it refines the threshold according to the value and position standard. HNUTA can estimate the best and worst value of the object. Compared between the top-k and the best value in the candidate set, it can remove the illegal object from the candidate set. This paper proposes top-k query in P2P network. It dynamically adjusts of the upper score according to the loss function. This method reduces the reply traffic by controlling the number of query replies. In addition, through experimental simulation and theoretical analysis, the proposed algorithm is superior to the current top-k algorithm. It consumes less bandwidth and has better efficiency.