After you create new WDs, you define exception directives that instruct Teradata WA how to monitor queries, and what to do if a query exceeds exception criteria while it is executing.
An exception directive consists of a set of exception criteria (exception metrics) and a set of exception actions (actions that Teradata WA takes when all of the metrics for a set of exception criteria are exceeded). If a request exceeds all exception metrics (for example, a request exceeds 1000 CPU seconds), it is potentially disqualified from the workload and conforms to the enabled exception actions.
When specifying multiple metrics in one exception criteria set for a WD, they act as a set of AND'ed conditions.
Multiple exception directives can be defined for a WD. When you define multiple exception directives for a WD with different sets of exception criteria but the same set of exception actions, each exception criteria set is treated as alternative (OR'd) conditions. See Handling Concurrent Multiple Exception Directives for a WD for guidelines Teradata WA follows when multiple exception directives are applicable at the same time for a WD.
It is recommended that you avoid overly complex combinations of exception criteria in an exception directive until you have experience about how your system performs.
Exception directives are operating environment-dependent. You can vary exception directives for different operating environments. In one operating environment, a WD may use several exception directives, while in another operating environment the same WD may not use any exception directives.
Setting Local Exception Directives
You can use Teradata WA to define local exception directives for a WD. A local exception directive applies only to the current WD. A global exception directive applies to several (or all) WDs. For instructions on creating global exception directives, see Teradata Viewpoint User Guide (B035-2206).