15.00 - EnableTempBLC - Teradata Database

Teradata Database Utilities

Product
Teradata Database
Release Number
15.00
Content Type
Configuration
Publication ID
B035-1102-015K
Language
English (United States)
Last Update
2018-09-25

EnableTempBLC

Purpose  

Determines whether temperature-based block-level compression (TBBLC) is enabled.

Field Group

Compression

Valid Settings

 

Setting

Description

TRUE

TBBLC is enabled. Tables using AUTOTEMP compression (specified in CREATE TABLE or ALTER TABLE statements) will have infrequently accessed data blocks automatically compressed for storage.

Note: In order to use TBBLC, BlockLevelCompression must be set to On.

FALSE

TBBLC is disabled. Data blocks are not compressed based on frequency of access.

Default

FALSE

Changes Take Effect

After the DBS Control Record has been written.

Usage Notes

When TBBLC is enabled, “AutoCylPackColdData” should be set to TRUE, and “DisableAutoCylPack” should be set to FALSE.

If TBBLC is disabled, tables that are set to use automatic temperature-based compression will behave like tables set to use manual compression until TBBLC is enabled again. The system default for whether tables use manual or automatic compression is set with the “DefaultTableMode” setting.

BLC enables data compression at the data block (DB) level of the Teradata Database file system. Compression reduces the amount of storage required for a given amount of data. The BlockLevelCompression field of DBS Control enables and disables BLC.

Data temperature refers to the frequency of access. Hot data is frequently accessed. Cold data is infrequently accessed. Warm data is accessed moderately frequently. TBBLC automatically compresses colder data to save storage space, and decompresses the data if it becomes hotter. At any time, different portions of a table, such as different partitions, may exist in different states of compression depending on their temperatures.

Related Topics

 

For more information on…

See…

Block-level compression

Database Administration.

BLOCKCOMPRESSION table attribute

SQL Data Definition Language.

DefaultTableMode setting

“DefaultTableMode” on page 296.

Ferret COMPRESS, UNCOMPRESS, and FORCE commands

Chapter 13: “Ferret Utility (ferret).”

Query bands for compression

SQL Data Definition Language.

Storage group of DBS Control settings

“Storage Group” on page 484.