Teradata WA follows these guidelines when multiple exception directives (multiple exception criteria/actions) are applicable at the same time for a WD.
Teradata WA evaluates all exception directives. It is possible that multiple exception directives are exceeded together. If so, Teradata WA performs all the corresponding exception actions that do not conflict.
A conflict occurs when two exception actions to be performed are either of the following:
- Abort and change WD
- Change to different WDs (for example, change to WD-A and change to WD-B)
Teradata WA follows these guidelines to resolve conflicting exception actions when necessary:
- Local exception actions take precedence over global exception actions.
- Teradata WA orders local and global exception actions to their defined precedence for resolving situations similar to the following case:
if Maximum Rows > 100, Change Workload to WD-M
if Sum Over All Nodes > 200, Change Workload to WD-N
If Maximum Rows and Sum Over All Nodes both exceed their limits at the same time, the defined precedence determines to which WD Teradata WA changes.
- If Teradata WA must perform several exception actions because one or more exception criteria occur simultaneously, Teradata WA always executes all Raise Alert, Run Program,and Post to Queue Table exception actions. Other actions occur as follows:
- If you did not specify Abort and Log or Abort on Select and Log, and you specified multiple global Change Workload exception actions, the global Change Workload exception action with highest precedence occurs. Teradata WA logs all other Change Workload exception actions as overridden.
- If you did not specify Abort and Log or Abort on Select and Log, and you specified multiple local Change Workload exception actions, the local Change Workload exception action with highest precedence occurs. Teradata WA logs all other Change Workload exception actions as overridden.
- If you did not specify Abort and Log or Abort on Select and Log, and you specified multiple global and local Change Workload exception actions, the local Change Workload exception action with highest precedence occurs, since local exception actions take precedence over global exception actions. Teradata WA logs all other Change Workload exception actions as overridden.
- Aborts take precedence over any Change Workload exception actions. If you specified Abort and Log or Abort on Select and Log, and you specified multiple global and local Change Workload exception actions, Teradata WA aborts the query and logs all Change Workload exception actions as overridden.