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 field is effective only when TBBLC is enabled.
1 through 90 days
Changes Take Effect
The first time the background compression task runs after the DBS Control Record has been written.
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.
|For more information on…||See…|
|Block-level compression||Database Design|
|BLOCKCOMPRESSION table attribute||SQL Data Definition Language - Syntax and Examples|
|Ferret COMPRESS, UNCOMPRESS, and FORCE commands||Ferret Utility (ferret)|
|Query bands for compression||SQL Data Definition Language - Syntax and Examples|
|Storage group of DBS Control fields||Storage Group|