17.10 - Use EXPLAIN to Analyze the Usefulness of Secondary Indexes - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQL Data Definition Language Detailed Topics

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Release Date
July 2021
Content Type
Programming Reference
Publication ID
B035-1184-171K
Language
English (United States)

Before a request is processed, the Optimizer estimates comparative costs to determine whether the use of a secondary index offers savings or is plausible. If not, it uses a different access method. You should test the performance of a secondary index before implementing it.

Use the SQL EXPLAIN request modifier to generate a description of the processing sequence to help determine whether a secondary index should be retained. See Teradata Vantage™ - SQL Data Manipulation Language, B035-1146.