RLPI索引:一种处理连续不确定XML索引

RLPI INDEX: AN INDEX PROCESSING CONTINUOUS UNCERTAIN XML DATA

针对目前连续不确定XML数据的概率阈值范围查询,提出一种新的包含路径索引和值索引的RLPI(Reverse Label Probabilistic Index)索引。RLPI路径索引以逆序标签路径作为索引项,通过逆序标签路径可区分不同路径上的同名节点,更具针对性地定位所需节点。RLPI值索引借鉴U树的思想,通过提前计算并存储叶子节点的相关信息,以减少查询中需处理的元素数目,并且其对满足任意连续pdf(probability density function)的不确定数据均适用。理论分析和实验结果表明,RLPI索引技术有效地提高了查询处理的性能。

Aiming at current probability threshold range query on continuous uncertain XML data,we put forward a new RLPI index（ reverse label probabilistic index）. RLPI index contains RLPI path index and RLPI value index. RLPI path index takes reverse label path as the index item,through reverse label path it can distinguish tag nodes with same name on different paths,and is more targeted to locate the desired nodes. RLPI value index gets reference from the idea of U Tree. It calculates in advance and stores some related information of leaf nodes in order to reduce the number of elements to be processed in a query. RLPI value index is applicable to uncertain data satisfied with any continuous pdf（ probability density function）. Theoretical analysis and experimental results show that this index technique greatly improves query processing performance.