An Approach for Retrieving Faster Query Results From Data Warehouse Using Synonymous Materialized Queries

摘要

The enterprise data warehouse stores an enormous amount of data collected from multiple sources for analytical processing and strategic decision making. The analytical processing is done using online analytical processing (OLAP) queries where the performance in terms of result retrieval time is an important factor. The major existing approaches for retrieving results from a data warehouse are multidimensional data cubes and materialized views that incur more storage, processing, and maintenance costs. The present study strives to achieve a simpler and faster query result retrieval approach from data warehouse with reduced storage space and minimal maintenance cost. The execution time of frequent queries is saved in the present approach by storing their results for reuse when the query is fired next time. The executed OLAP queries are stored along with the query results and necessary metadata information in a relational database is referred as materialized query database (MQDB). The tables, fields, functions, relational operators, and criteria used in the input query are matched with those of stored query, and if they are found to be same, then the input query and the stored query are considered as a synonymous query. Further, the stored query is checked for incremental updates, and if no incremental updates are required, then the existing stored results are fetched from MQDB. On the other hand, if the stored query requires an incremental update of results, then the processing of only incremental result is considered from data marts. The performance of MQDB model is evaluated by comparing with the developed novel approach, and it is observed that, using MQDB, a significant reduction in query processing time is achieved as compared to the major existing approaches. The developed model will be useful for the organizations keeping their historical records in the data warehouse.