Adaptation of XML storage schema in VXMLR

The efficiency of an XML management system depends mainly on its storage schema. Designing storage schema based on users' queries can improve its performance significantly. This paper introduces the technique of XML storage schema adaptation in the VXMLR system. Based on history queries, the VXMLR system automatically adjusts its storage schema for speeding up query processing. First, some appropriate mapping rules are derived from the history queries, and then initial storage schema is generated by using these mapping rules. Second, under given space constraint and with the history queries, some relational tables are selected for vertical partitioning or redundant storage so that these tables can be accessed as fast as possible. Four kinds of schema adaptation strategies are presented, in which two are used for automatic schema adaptation. Experimental results validate the practicability and effectiveness of our proposed approach.