Creation of Optimal Materialized Views Using Bitmap Index and Firefly Algorithm in Data Warehouse

A sensitive issue in designing the data warehouse is using some mechanics like summary tables (materialized views) and indexes for speeding up the query processing time. Due to storage space constraints, it is impossible to materialize all views in a data warehouse; therefore, many researchers have proposed various methodologies aiming to solve this problem by selecting the optimal set of materialized views. In this paper, we define a new efficient framework to create optimal materialized views depending on three factors (MV processing time, MV storage space and MV access frequency) by applying aggregations over bitmap index and select optimal one using Firefly algorithm (FA) for optimizing complex queries performance and reducing queries response time. The results of the proposed system show that bitmap index performs best results for aggregation queries where the aggregations response time on one field in our DW selected directly to base tables was found to be 757 milliseconds whereas the response time of these aggregations on the same field over bitmap index was found to be 489 milliseconds. Also, results prove that the firefly algorithm was effective in term of creating optimal materialized view time.