17.00 - Memory: TIM Columns - Teradata Database

Teradata Vantage™ - Resource Usage Macros and Tables

Advanced SQL Engine
Teradata Database
June 2020
User Guide

These columns represent information about the VH (Very Hot) cache, which holds the hottest permanent table cylinders.

Tables that are assigned a temperature of very hot are kept in the FSG cache as long as they:

  • Stay very hot.
  • Fit into the memory assigned. If the tables cannot fit, the FSG cache considers a sorted list of the hottest segments and assigns them to the very hot cache in temperature sorted order. The temperature of the segment is hot enough to qualify.

The temperature takes into account both physical and logical disk accesses and cache hits (such as, physical and logical I/Os).

Column Name Mode Description Data Type
VHAgedOut count Number of data segments that were aged out of VH cache. FLOAT
VHAgedOutKB count Volume of data segments in KB that were aged out of VH cache. FLOAT
VHLogicalDBRead count Number of logical reads from VH cache. FLOAT
VHLogicalDBReadKB count Volume of logical reads in KB from VH cache. FLOAT
VHPhysicalDBRead count Number of very hot reads that were handled by physical disk I/O due to a VH cache miss (that is, data not found in the VH cache). FLOAT
VHPhysicalDBReadKB count Volume of very hot reads in KB that were handled by physical disk
I/O due to a VH cache miss. FLOAT
VHCacheInuseKB track Size of VH cache in KB currently in use. FLOAT