Cache Based Query Optimization Approach in Distributed Database
Query optimization in distributed databases is explicitly needed in many aspects of the optimization process, often making it imperative for the optimizer to consult underlying data sources while doing cost based optimization. This not only increases the cost of optimization, but also affects the trade-offs involved in the optimization process significantly. The leading cost in this optimization process is the cost of costing that traditionally has been considered insignificant. The optimizer can only afford a few rounds of messages to the under-lying data sources and hence the optimization techniques in this environment must be geared toward gathering all the required cost information with minimal communication. In this paper, a cache based query optimization model has been proposed which shows better hit ratio even for the initial queries made since local cache has been used instead of global cache. A cache is implanted between the local optimizer and local database. Whenever a query is given to a local optimizer, local optimizer first checks the cache rather than fetching the data directly from the database. In case, if the solution of query can be obtained from the cache, it results in saving a huge amount of computation time as accessing a cache is faster than accessing the database. The proposed cost optimization model works on the basis of four different factors i.e. server distance, server capacity, server load and current queue length to provide optimal node where query should be executed.
Keywords: distributed database, cost optimizer, query optimization, cache, local cache, server load.
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ABOUT THE AUTHORS
Mantu Kumar
Mantu Kumar is a student of Master of Technology in Computer Science and Engineering, Maharishi Markandeshwar University, Mullana, Ambala, India. He worked as Computer faculty for one year after completion of Master of Computer Application from Madurai Kamaraj University, Mudurai, Tamilnadu, India. He also worked 1.5 years as a software developer and trainer after completion of Bachelor of Computer Application in 2005. He has published one paper in international journal. His research area is query optimization, concurrency control, security in distributed database and network security.
Neera Batra
Dr. Neera Batra received PhD in Computer Science & Engineering from Maharishi Markandeshwar University, Mullana, Ambala and Master of Technology in Computer Science & Engineering from Kurukshetra University, Kurukshetra. Dr. Neera Batra is in teaching and Research & Development since 2007. She has supervised several M.Tech thesis. She has published more than 15 research papers in International/National journals and refereed international/national conferences. Her research interests are in concurrency control, query optimization, security, load balancing, check pointing & recovery, access control in distributed database and network security.
Hemant Aggarwal
Hemant Aggarwal is an employee of Infosys Ltd. Bangalore working as system engineer. He has been working since 2009 after completing B.tech in computer science from Kurukshetra University, Kurukshetra. He has published three papers in international/National journals. His research area is query optimization, security in distributed database and network security.
Mantu Kumar
Mantu Kumar is a student of Master of Technology in Computer Science and Engineering, Maharishi Markandeshwar University, Mullana, Ambala, India. He worked as Computer faculty for one year after completion of Master of Computer Application from Madurai Kamaraj University, Mudurai, Tamilnadu, India. He also worked 1.5 years as a software developer and trainer after completion of Bachelor of Computer Application in 2005. He has published one paper in international journal. His research area is query optimization, concurrency control, security in distributed database and network security.
Neera Batra
Dr. Neera Batra received PhD in Computer Science & Engineering from Maharishi Markandeshwar University, Mullana, Ambala and Master of Technology in Computer Science & Engineering from Kurukshetra University, Kurukshetra. Dr. Neera Batra is in teaching and Research & Development since 2007. She has supervised several M.Tech thesis. She has published more than 15 research papers in International/National journals and refereed international/national conferences. Her research interests are in concurrency control, query optimization, security, load balancing, check pointing & recovery, access control in distributed database and network security.
Hemant Aggarwal
Hemant Aggarwal is an employee of Infosys Ltd. Bangalore working as system engineer. He has been working since 2009 after completing B.tech in computer science from Kurukshetra University, Kurukshetra. He has published three papers in international/National journals. His research area is query optimization, security in distributed database and network security.
