Maintaining Materialized XPath Views Incrementally by Program Transformation

摘要

Extensive studies on incremental maintenance of materialized views for relational data source have proved that incremental maintenance of materialized views can bring a lot of performance benefits. It is still a challenge for incremental maintenance of materialized views for semi-structured data source although some works have put their emphasis on it. This paper proposes a novel approach to implement incremental maintenance of materialized Xpath view based on the theory of incremental computation and program transformation. The characteristics of this approach are: (1) The incremental maintenance program is created automatically for a specific materialized Xpath view and a specific update in XML data source; (2) Program transformation technique is used to create incremental maintenance program; (3) The incremental maintenance program is written in Xquery language and can be executed by any Xquery engine; (4) The only auxiliary data to maintain the materialized Xpath view is the incremental maintenance program and its size cost is very small. Experiments have shown that this approach outperforms view recomputation.