What is meant by heuristic optimisation, Database Management System

Assignment Help:

What is meant by heuristic optimisation?Discuss the major heuristics that are applied during query optimisation.                                                                                       

Ans:   In heuristic opimization, heuristics are employed to decrease the cost of optimization in place of analyzing the number of dissimilar plans to find out the optimal plan. For instance A analyzing optimizer would make use of the rule 'perform selection operation as early as possible' without finding out whether the cost is decreased by this transformation.  Heuristics approach generally assists to reduce the cost but not always. The heuristics which are applied during query optimization are:

a)      Pushes the selection and projection operations down the query tree

b)      Left-deep join trees- convenient for pipelined evaluation

c)       Non- left-deep join trees


Related Discussions:- What is meant by heuristic optimisation

Durability-transaction , Durability : This property necessitates that once ...

Durability : This property necessitates that once a transaction has committed, the changes made by it be never lost because of subsequent failure. Thus, a transaction is also a bas

Related fields in a database are grouped in which form, Related fields in a...

Related fields in a database are grouped in which form? Related data fields in a database are grouped to form a data record. (A record is a collection of related fields)

Query to delete constraint from alter table, A constraint named less_than_2...

A constraint named less_than_20 was defined on the field date_of_birth of table student. Delete this constraint. ALTER TABLE student DROP CONSTRAINT less_than_20;

Explain pipelining, Explain pipelining.        Ans: In order to describ...

Explain pipelining.        Ans: In order to describe pipelining in simple terms, think of it as breaking down processor functions into smaller and smaller parts. For instance,

Windows 8 Administrative Tools, Which two tools are used to administer user...

Which two tools are used to administer users for Active Directory?

There are two major types of fragmentation, There are two major types of fr...

There are two major types of fragmentation: Horizontal& Vertical. Horizontal fragments, as the name suggests are subsets of tuples and vertical fragments are subsets of attributes

Explain the concept of data mining, Question 1 Explain the concept of Fore...

Question 1 Explain the concept of Foreign Key. How a foreign key differs from a Primary Key? Can the Foreign Key accept nulls? Question 2 With a necessary example explain (i)

What are segments in oracle, What are segments in oracle? Segments - Ea...

What are segments in oracle? Segments - Each table has single field of disk space, known as segment, set aside for it in the tablespace. Segments consist of contiguous sections

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd