17.00 - Exception Action Conflict Resolution - Teradata Workload Management

Teradata Vantageā„¢ - Workload Management User Guide

prodname
Advanced SQL Engine
Teradata Workload Management
vrm_release
17.00
created_date
June 2020
category
Administration
User Guide
featnum
B035-1197-170K

One request could trigger multiple exceptions. If that happens, TASM performs all exception actions that do not conflict. For example, TASM always executes all Send Alert, Run Program, and Post to QTable actions because they do not conflict. TASM always performs the associated logging also.

A conflict occurs when two simultaneous exceptions call for the following actions against a request:
  • Abort versus Change Workload
  • Change Workload to: Workload A versus Change Workload to: Workload B
TASM follows these rules to resolve exception action conflicts:
  • Abort actions take precedence over Change Workload to: actions
  • Change Workload to: is applied based on the workload management method the workload uses, in ascending order of precedence:
    • Timeshare tier
    • SLG tier
    • Tactical tier
TASM resolves further exception action conflicts with these rules, which favor the lower workload classification:
Conflict TASM Rule
Two Change Workload to: actions move a request to the Timeshare tier but to workloads on different levels. The request moves into the workload on the lower level. If both actions move the request to the same level, the request moves into the workload whose name appears first in the alphabet.
Two Change Workload to: actions move a request to the SLG tier but to workloads on different levels in that tier. The request moves into the workload on the lower level. If both actions move the request to the same level, the request moves into the workload with the lower workload allocation percentage value. If the two workloads have the same allocation percentage value, the request moves into the workload whose name appears first in the alphabet.

In every case, TASM logs the exception actions that it did not perform into TdwmExceptionLog and indicates that they were overridden.