17.00 - 17.05 - Considerations - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - Teradata® Virtual Storage

Product
Advanced SQL Engine
Teradata Database
Release Number
17.00
17.05
Release Date
June 2020
Content Type
Configuration
Publication ID
B035-1179-170K
Language
English (United States)

Licensing

Teradata VS hybrid storage support is available with Teradata Database Enterprise Tier licensing. For more information, contact your Teradata sales representative.

Temperature-based block-level data compression (TBBLC) and temperature-based data migration between fast and slow storage media is available to all Teradata Database customers, regardless of licensing tier. For more information about TBBLC, see Teradata Vantage™ - Database Design, B035-1094 and Teradata Vantage™ - Database Utilities , B035-1102 .

Initial Data Temperature

When data is loaded into a new table, the system does not know whether that data will be hot (accessed frequently) or cold (accessed infrequently), so it is initially assigned the temperature specified by the appropriate Storage setting in DBS Control. Typically, you can allow the system to set the temperature according to this setting.

Over time, Teradata VS monitors data access patterns, assigns table data a temperature based on those access patterns, and moves data between faster and slower storage to place the hotter data on faster physical storage.

For tables with very specific data access requirements, you can use the TVSTemperature query band (at load time) or the Ferret FORCE command (soon after a table is created) to expedite the time required to place the data into the proper storage grade.

Use the TVSTemperature query band and the Ferret FORCE command only if you are certain that the standard background migration will not move the data to appropriate storage quickly enough for your needs.

Teradata VS monitors frequency of data access and adjusts data temperatures dynamically as it monitors frequency of data access. Consequently, temperatures can change from those specified using the TVSTemperature query band or the FORCE command, if the measured frequency of actual data access differs from the temperature that is initially set.