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Learn T-SQL Querying
book

Learn T-SQL Querying

by Pedro Lopes, Pam Lahoud
May 2019
Intermediate to advanced content levelIntermediate to advanced
484 pages
11h 23m
English
Packt Publishing
Content preview from Learn T-SQL Querying

Introducing the Cardinality Estimator

In Chapter 2, Understanding Query Processing, we discussed how the Query Optimizer is a fundamental piece of the overall query processor. In this chapter, we will dig deeper into the core component of cost-based query optimization: the Cardinality Estimator (CE).

As the name suggests, the role of the CE is to provide fundamental estimation input to the query optimization process. For example, the cardinality of a table that contains the name of every living human on Earth today is about 7,600,000,000. But if a predicate is applied on this table to find only inhabitants of the United States of America, the cardinality after the predicate is applied is only 327,000,000. Reading through 7,600,000,000 or ...

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Publisher Resources

ISBN: 9781789348811Supplemental Content