International Journal of Applied Engineering Research ISSN 0973-4562 Volume 12, Number 23 (2017) pp. 13927-13932 © Research India Publications. http://www.ripublication.com 13927 Approaches for Query Optimization using Materialized Views in Dynamic Distributed Environment: A Review Abhijeet R. Raipurkar Research Scholar, Department of Computer Science and Engineering Shri Ramdeobaba College of Engineering and Management, Gittikhadan, Katol Road, Nagpur-440013, Maharashtra, India. Orcid Id: 0000-0003-2327-8358 Manoj B. Chandak Professor and Head, Department of Computer Science and Engineering, Shri Ramdeobaba College of Engineering and Management, Gittikhadan, Katol Road, Nagpur 440013 Maharashtra, India. Orcid Id: 0000-0002-0103-4224 Abstract Data warehouse in present scenario contains data from multiple heterogeneous data source. Data sources are dynamic in nature as information schema are continuously evolving and changing. In loosely coupled environment data sources are independent hence updates from various data sources are synchronous. Frequency of addition, deletion and updation operations on based relation have increased because of dynamic nature of data source. Analyzing query response time in distributed heterogeneous environment consists of communication part to establish a connection with heterogeneous data source and data transmission part to transfer data across distributed sites. Selection and maintenance of views is vital task in order to provide maximum efficiency by cutting down query processing and maintenance cost. Integrating data from distributed dynamic environment is big challenge. Querying data from heterogeneous sources is an important research issues in distributed environment. Materialized Views can be used to precompute and store results in data warehouse. Data warehouses, decision support applications and mobile computing environment widely use materialized views for reducing query response time. In distributed environment materialized views are replicated at multiple sites and concurrent updated are performed at multiple sites whenever underlying base relations are modified. Various conflict resolution methods are employed while replicating views at distributed sites. View maintenance cost is enlarged if all the views are materialized in distributed environment at multiple sites but it gives best performance for user queries. Using materializing views in data warehouse includes challenge of identification of which views to materialize, performance consideration, view adaption, view maintenance. We present various approaches for query optimization on materialized views in distributed dynamic environment proposed by researchers. In this paper comparative studies on research work of various authors have been surveyed based on important query optimization parameters. Keywords: Materialized views; view maintenance; data grids; query optimization; distributed environment INTRODUCTION The requirement of data in heterogeneous database system must be effective integration with the widespread use of network platform in order to better data sharing and data processing. Data integration and maintenance from distributed dynamic source has become important for various applications. The integrated data is usually stored as materialized views to allow better access, performance, and high availability in data warehouse. Data warehouse (DW) generalizes and consolidated data in multidimensional space. Data warehouse also provide online analytical processing (OLAP) tools for interactive analysis of data. Data warehouse is accessed through queries which generally interact with views which are stored in data warehouse. These views are called as materialized views. While designing data warehouse important decision is to formulate materialized views which are most suitable for OLAP queries. Benefit of materialized view is faster response time and enhanced performance. The most vital task in data warehousing environment is to keep materialized views up to date by using various view maintenance technique. The most important challenges while designing data warehouse is to select which views to materialize. If OLAP (on-line analytical processing) queries are run against huge data volume in data warehouse then it may result in unacceptable query performance. OLAP queries are very complex and involve aggregation. OLAP queries are critical as it access million of records and response time is effective