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. 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 t1You also can select 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 columns or to use the WHERE clause.