17.10 - BLOCKCOMPRESSION - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQL Data Definition Language Detailed Topics

Advanced SQL Engine
Teradata Database
Release Number
July 2021
English (United States)
Last Update

Use this option to set the block compression state of a join index.

The following table lists the available options for BLOCKCOMPRESSION.

Option Description
AUTOTEMP The compressed state of the data in the join index can be changed by Vantage at any time based on its temperature.

You can still issue query band options or Ferret commands, but if the compressed state of the data does not match its temperature, such changes might be undone by the system over time.

DEFAULT The definition of whether the join index uses the MANUAL, AUTOTEMP or NEVER compression options is determined by the DBS Control flag DefaultTableMode. For more information, see Teradata Vantage™ - Database Utilities, B035-1102.
MANUAL The compressed state of the data in the join index does not change unless you take specific action to do so using Ferret commands.
NEVER The join index is not compressed even if the DBS Control block compression settings indicate otherwise.

This means that Vantage rejects Ferret commands to manually compress the join index, but Ferret commands to decompress the index are valid.

See Teradata Vantage™ - Database Utilities, B035-1102 for information about how to use the Ferret utility.