17.10 - Choosing a Software-based Compression Scheme - Advanced SQL Engine - Teradata Database

Teradata Vantageā„¢ - Database Design

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Published
July 2021
Language
English (United States)
Last Update
2021-07-27
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In some cases, such as when column values are mostly unique, algorithmic compression can provide better compression results than multivalue compression. Because multivalue compression can coexist with algorithmic compression, users have the flexibility of an IF-ELSE option: either compressing values from a dictionary or using a custom compression algorithm.

Algorithmic compression has a fairly high overhead each time the compressed column is accessed during the execution of a query. It is best used for columns that are used only for the final projected answer set.