15.10 - Storage Group - Teradata Database

Teradata Database Teradata Virtual Storage

prodname
Teradata Database
vrm_release
15.10
category
Configuration
featnum
B035-1179-151K

Each field in the Storage group specifies the initial temperature that will be assigned to data loaded or inserted into empty subtables of a particular type. The temperature represents the expected frequency of access to that data, and can determine whether the data is compressed, and where the data is stored.

Note: Because the frequency of access is continually monitored by Teradata Database, the temperature can change over time from the initial temperature setting.

The individual Storage setting names and defaults are listed below. These fields are relevant and visible only when temperature-based block level compression is enabled, or on systems that have licensed Teradata Virtual Storage (VS).

 

Storage Field

Default Temperature

DEPOT Temperature

HOT

GLOBAL TEMP Fallback Temperature

WARM

GLOBAL TEMP Fallback CLOB Temperature

WARM

GLOBAL TEMP Primary Temperature

WARM

GLOBAL TEMP Primary CLOB Temperature

WARM

PERMANENT JOURNAL Temperature

HOT

PERM Fallback Temperature

WARM

PERM Fallback CLOB Temperature

WARM

PERM Primary Temperature

The Parallel Upgrade Tool (PUT) sets the default for PERM primary data based on the system configuration. For some configurations the default is HOT.

WARM

PERM Primary CLOB Temperature

WARM

SPOOL Temperature

HOT

WAL Temperature

HOT

All Other Temperature

Controls initial data temperature set for data loaded into empty subtables that are not specifically controlled by other Storage group fields.

WARM

 

Setting

Description

HOT

Data is expected to be accessed frequently.

WARM

Data is expected to be accessed moderately frequently.

COLD

Data is expected to be accessed infrequently.

DEFAULT

Uses the default temperature for this type of data. Resets the field to the factory default value for the specified table or data type.

After the DBS Control record has been written.

The Storage field settings are honored when data is loaded into empty tables by any of the following techniques:

  • INSERT/INSERT ... SELECT statement
  • CREATE TABLE AS ... WITH DATA statement
  • CREATE JI statement
  • Load utilities TPump, FastLoad, MultiLoad, Teradata Parallel Transporter
  • Teradata Archive/Recovery (ARC) utility
  • Table Rebuild utility
  • Note: The TVSTemperature query bands and the Ferret FORCE command override these storage settings.

    Because data temperature is assigned at the cylinder level, after initial assignment, data in different partitions of a partitioned table can have different temperatures.

    For systems licensed to use Teradata VS, data can be automatically moved (migrated) to faster or slower grades of storage as data temperatures change due to changing data access patterns.