16.20 - Why You Need To Collect Statistics - Teradata Database - Teradata Vantage NewSQL Engine

Teradata Vantage™ SQL Data Definition Language Detailed Topics

Product
Teradata Database
Teradata Vantage NewSQL Engine
Release Number
16.20
Release Date
March 2019
Content Type
Programming Reference
Publication ID
B035-1184-162K
Language
English (United States)

The purpose of collecting statistics is to compute statistical data that the Optimizer uses to optimize table access and join plans. The computed statistical data is retained in a synopsis data structure that is stored in the data dictionary for use during the optimizing phase of SQL request parsing.

Accurate demographics enable the Optimizer to determine the least costly access and join plans for a query. Accurate table demographic information is especially important when data to be accessed using a column or index might be skewed.