15.00 - TempBLCRescanPeriod - 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

TempBLCRescanPeriod

Purpose  

The number of days the background temperature-based block-level compression (TBBLC) task waits before revalidating the state of TBBLC data to reconfirm that data is appropriately compressed and uncompressed based on data temperature. Because data temperature is a relative measure, temperatures can change even if that data is not directly accessed or modified.

This setting is effective only when TBBLC is enabled.

Field Group

Compression

Valid Range

1 through 90 days

Default

7 days

Changes Take Effect

The first time the background compression task runs after the DBS Control Record has been written.

Usage Notes

TBBLC data is revalidated automatically whenever the system is restarted.

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.

Enabling TBBLC

“EnableTempBLC”.

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”.