Request Throttles | Teradata Vantage - 17.00 - Request Throttles - 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

The most popular use of throttles is to limit concurrent requests. When you enable a throttle rule, TASM counts the active requests the rule applies to. When a new request is ready to execute, TASM compares the request count with the rule limit. If the count is below the limit, the request runs immediately. If the count is equal to or above the limit, TASM either rejects the request or puts it in a delay queue. Most throttles delay requests rather than reject them.

When system activity falls below the throttle limit, the system runs delayed requests in the order you select for releasing the throttle delay queue:
  • By time delayed: The requests delayed the longest are released first
  • By workload priority: The request from the highest-priority workload is released first
The Order the Throttle Delay Queue option is available in the General area of Viewpoint Workload Designer on the Other tab.

If a delayed request starts to run, it cannot be delayed again.

If a request is subject to multiple throttles, all throttles must be below the limit before the request can run.