INDEXES' OPTIMAL SELECTION FOR DATA WAREHOUSE QUALITY

Query answering in DW performance is highly improved by bitmap Index. The efficiency of complex query processing greatly increased through the use of Boolean operations (AND, OR, NOT, etc.) in the selection predicate on multiple indexes and uses efficient storage space for attribute with low cardinality. The most important metrics are space and time for evaluating the performance of an index, and in case of bitmap index; the focus was on time optimal index. In this paper, we are proposing an algorithm to increase query performance and reduce the response time using boolean operations (AND, OR) called multi Bitmap Index M-BI, bitmap index has been implemented on a group of tables, and then the implementation of a bitmap index on a multiple columns in the table, as well as retrieve a query on any two columns in the table at the same time with swap the columns depending on the value cardinality. This study shows that the proposed method is better than other existing techniques of bitmap indexing on single column and single table. One of the results showed that the performance of queries in terms of time of access from multi Bitmap Index M-BI selection was found to be 04 milliseconds (MS) while those queries directly selected from DW was found to be 38 milliseconds. This shows the performance of query through Bitmap Index access is better than those directly access through DW by 892.10%.