Teradata Database detects classification criteria before executing queries. Classification criteria identifies the “Who,” “What,” and “Where” of requests as a way of grouping them for better control, to ensure resources are allocated as appropriate to your needs.
For example, to allocate more resources to requests originating from a particular department in your company, your classification criteria might specify the application or account that corresponds to those requests. Conversely, using classification criteria, you can isolate workloads that you want to assign lower priorities.
You can choose up to six classification criteria. It is recommended that you select at least one item from the “Who” criteria; you can combine additional criteria in accord with the following limitations.
- You cannot select a classification type more than once.
- You cannot combine a utility type with anything other than a “Who” characteristic, so if you pick a utility as criteria 2, criteria 3 must be a “Who” criteria item. If your second criteria item is a “What” or “Where,” you cannot follow it with a utility.
If you do not specify classification attributes for a WD, Teradata WA will initially not place any queries into that WD. However, you could use that WD as a lower-priority WD, for example, when queries encounter run-time exceptions in their original WDs and are downgraded to a lower priority WD.