16.10 - Skewed Query Processing Across Nodes - Teradata Database

Teradata Database Administration

Product
Teradata Database
Release Number
16.10
Release Date
April 2018
Content Type
Administration
Publication ID
B035-1093-161K
Language
English (United States)

Parallel node efficiency is a matter of how evenly the workload is shared among nodes. The more evenly the nodes share the work, the higher the efficiency.

You can calculate parallel node efficiency by dividing average node utilization by maximum node utilization, and identify skewed processing across nodes.

IF parallel node 
efficiency … THEN …
is nearly 100% the better the nodes are working together.
falls significantly below 100% in that time period, one or a few nodes are working harder than the others.
falls below 60% more often than a couple of sampling periods your installation is not taking advantage of the parallel architecture.

Possible causes of skewed node processing include:

  • Down node
  • Non-Teradata Database application running on a TPA node
  • Co-existence system where the number of AMPs per node is not optimally balanced with different node powers.
  • Poor AMP efficiency