Research And Application Of Materialized View Maintenance Strategy

A Data Warehouse contains large amounts of data and supports the complexity of query forms. How to satisfy the standard of the query efficiency is one of the problems faced by Data Warehouses, Materialized view technology is the important method to solve this problem, but it need extra system space to store, and it need maintenance at price of system cost, so the selection of materialized views is an important research topic.Static materialized view choice strategies are limited to the situation known to query and the inquiries Data Warehouse supports can hardly be predicted, so dynamic materialized view choice strategies are introduced. A dynamic adjustment standard of materialized views is developed, a dynamic materialized view choice strategy in the basic of queries is established and it is elaborated in the aspects of its thinking, architecture and workflow through the research on materialized view choice strategies, and detailed analysis of key issues in dynamic materialized view choice strategies.A new strategy named TVCS(Top-Views-Choice-Strategic) to choose materialized views is put forward based on a more accurate simulation of the form of materialized views in the data warehouse, TVCS not only reduces the number of all views by choosing the set of the relevant views in the whole views, but also uses the relationship between father and son views in reducing the number of views in order to reduce the complexity of choice algorithm, which reduces unnecessary cost calculation on the materialized views selection process. More precise cost of materialized views is made in order to further optimize results through amending the importance of materialized view.TVCS is put into use in the decision support system in colleges and universities. TVCS's running time is less than Semi-Greedy algorithm(SG) with the same space constraints in the similarly stable day-to-day business inquiries, that TVCS is superior to SG in the inquiry efficiency; SG shows frequent jitter of inquiries'time, and the performance of the TVCS is more stable, that TVCS is better than SG in the query efficiency's stability, which proved TVCS'efficiency and stability.