Introduction to Query Processing and Optimization
Query processing is the scientific art of obtaining the desired information from a database system in a predictable and reliable fashion. Database systems must be able to respond to requests for information from the user i.e. process queries. In large database systems, which may be running on un-predictable and volatile environments, it is difficult to produce efficient database query plans based on information available solely at compile time. Getting the database results in a timely manner deals with the technique of query optimization. Efficient processing of queries is an important requirement in many interactive environments that involve massive amounts of data. Efficient query processing in domains such as the Web, multimedia search, and distributed systems has shown a great impact on performance.