16.20 - Overview - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQL Operators and User-Defined Functions

Product
Advanced SQL Engine
Teradata Database
Release Number
16.20
Release Date
April 2020
Content Type
Administration
Programming Reference
Publication ID
B035-1210-162K
Language
English (United States)

The following sections describe the functions that you can use with algorithmic compression (ALC) to compress and uncompress column data of character or byte type. Compression of data reduces space usage and the size of disk I/Os.

If the compression and decompression functions described here are not optimal for your data, you can write your own user-defined functions (UDFs) to compress and uncompress table columns.

Using ALC together with block-level compression (BLC) may degrade performance, so this practice is not recommended.

Prerequisites

The functions described here are embedded services system functions. For information on activating and invoking embedded services functions, see "Embedded Services System Functions" in Teradata Vantage™ - SQL Functions, Expressions, and Predicates, B035-1145.

FOR more information on... SEE...
ALC
  • “COMPRESS and DECOMPRESS Phrases” and “CREATE TABLE” in Teradata Vantage™ - SQL Data Definition Language Syntax and Examples, B035-1144.
writing UDFs for ALC
  • “Defining Functions for Algorithmic Compression” in Teradata Vantage™ - SQL External Routine Programming , B035-1147 .
compression methods supported by Teradata Database and a comparison of the various methods
  • “Using Data Compression” in Teradata Vantage™ - Database Design, B035-1094.
  • “Compression Methods” in Teradata Vantage™ - Database Design, B035-1094.