PSP：一种高效的偏序域上skyline查询处理方法

为解决偏序域上的skyline查询问题,本文提出一种高效的偏序域上的skyline查询处理方法,来满足人们对查询效率日益增长的需求.首先,为提高偏序域上skyline的查询效率,将倒排索引引入skyline查询,提出一种基于倒排的索引结构.其次,提出基础算法(Basic Partially-ordered Skyline Processing based on inverted index,PSP_B),PSP_B包含两个阶段:第一阶段,能够通过映射将偏序域转化成全序域,并建立倒排索引;第二阶段,通过倒排索引提前找到扫描结束点,得到最终的skyline结果.再次,在PSP_B的基础上,进一步提出优化算法(Improved Partially-ordered Skyline Processing based on inverted index,PSP_I).PSP_I通过先分组再建索引的方法能够进一步提高计算效率.最后,用大量的实验证明本文所提算法的正确性和高效性.

PSP:An Efficient Skyline Computation Method for Partially Ordered Domains

In order to solve the skyline query problem in partial order domain, this paper proposes an efficient query processing method for the skyline query in the partial order domain to meet people''s increasing demand for query efficiency. Firstly, in order to improve the query efficiency of skyline on partially ordered domains, this paper introduces the inverted index into the skyline query and proposes an index structure based on the inverted index. Secondly, the basic algorithm PSP_B (Basic Partially-ordered Skyline Processing based on inverted index, PSP_B) is proposed. The PSP_B consists of two phases: in the first step, each partially ordered domain is converted into two fully ordered domains through mapping function, and then each fully ordered dimension is managed through the inverted index; in the second step, the scan end point is found through scanning the inverted index and the result set is obtained. Thirdly, based on the PSP_B, this paper further proposes an optimization algorithm PSP_I (Improved Partially-ordered Skyline Processing based on inverted index, PSP_I). The PSP_I can further improve the computational efficiency by grouping the data in advance and then indexing them. Finally, a large number of experiments prove the correctness and efficiency of the proposed algorithm.