Heatmap Table Function and Macro (tdheatmap and tdheatmap_m) | Teradata Vantage - Heatmap Table Function and Macro (tdheatmap and tdheatmap_m) - Advanced SQL Engine - Teradata Database

SQL Operators and User-Defined Functions
Product
Advanced SQL Engine
Teradata Database
Release Number
17.00
Published
September 2020
Language
English (United States)
Last Update
2023-04-27
dita:mapPath
qqu1556127655717.ditamap
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lze1555437562152.ditaval
dita:id
B035-1210
lifecycle
previous
Product Category
Teradata Vantage™

Purpose

The tdheatmap table function provides a frequency of access report for database objects on a specific AMP. To use this function, the Temperature-Based Block-Level Compression feature must be enabled, or you must have licensed the Teradata Virtual Storage feature. With tdheatmap, you can view the relative temperature of tables and data, the tables or cylinders targeted for the Teradata Intelligent Memory (TIM) cache, and the temperature ranges the tables occupy.

Data temperature reflects the frequency of data access. Hot data is the most frequently accessed. Cold data is the least frequently accessed. Warm data is moderately accessed.

There are different ways to invoke tdheatmap:
  • SELECT * FROM TABLE (tdheatmap(amp_number)) AS t1

    You also can select particular columns when using the tdheatmap function, but not when using the tdheatmap_m macro.

  • Use the tdheatmap_m macro.
  • Use the tdheatmap function to create a vew to invoke the heatmap on the same AMP for subsequent invocations.

    Use the view to SELECT particular columns or to use the WHERE clause.

Syntax

tdheatmap ( amp_number )
amp_number
The AMP number on which tdheatmap is to be executed.