System Throttles | Teradata Vantage - 17.00 - System 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

System throttles control the concurrency of all requests, or a specified subset of requests, across the entire system. TASM rejects or delays requests controlled by system throttles. System throttles can use all classification criteria.

System throttles provide value when workload throttles are not suitable. System throttles are workload-independent and can manage requests across broader dimensions than workload throttles.

Choose from the following three Rule Type options when you create a system throttle:
Collective
Provides the least granular control. TASM treats all requests that qualify for this throttle as one group. If the requests are delayed, the delay is based on the concurrency level of the entire group. For example, users Jay, Kay, and May are the classification criteria for a system throttle rule with a limit of 3 requests. With the Collective option, all the users together cannot have more than 3 requests running at the same time.
Individual
Treats each user or object (such as a specific account) independently. If the throttle affects multiple objects, TASM counts each separately. If only one object is associated with this throttle, the individual and the collective types act the same. If a system throttle with users Jay, Kay, and May and a limit of 3 requests has the Individual option, then each of those users can have up to 3 requests running at the same time. When using the Individual option, you must specify objects of only one kind in the rule classification criteria. If there are multiple objects types specified (for example, users and accounts or users and profiles), the Collective option is used. The Individual option does not support query band criteria.
Member
Provides the most granular control. TASM treats each user in a throttled object (such as account) independently of other users in that account. The intent of the Member option is to enable objects that represent groups of users, such as accounts and profiles, to be used as the classification criteria for the rule. The rule specifies the group, and any member of the group is covered by the rule. For example, users Jay, Kay, and May are associated with account ShoeDept. If there is a system throttle rule with a session limit of 3, classification criteria of account ShoeDept, and the Member option, then each of the users with the ShoeDept account can have up to 3 requests running at the same time.
Tip: One way to remember the difference between these different rule types is: one, many, and many more.
  • One: Collective is one throttle limit value, shared by the throttled objects.
  • Many: Individual can be many throttle limit values, one for each throttled object.
  • Many more: Member can be many more throttle limit values, depending on the throttled object and whether that object contains many other objects.