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Global Throttle Manager

The Global Throttle Manager manages the Façade Throttle Manager and Service Throttle Manager. The Global Throttle Manager reports throttle usage to the Central Logger.

The Global Throttle Manager component maintains the state of all the global throttles in both Façades (Façade Throttles) and Routers (Service Throttles). The Global Throttle Manager exchanges the states of global throttles with active Façade Throttle Managers and Service Throttle Managers.

The Global Throttle Manager component provides the mechanism to evenly distribute the global throttles among TIBCO API Exchange Gatewayserver instances.

The Global Throttle Manager component allows you to implement simple group throttles. Below are few examples of throttles types that are used in the Façade or Router as global throttles:

−	Commercial throttles implement gross usage agreements.

−	Partner throttles act to limit a partner’s impact on internal services.

−	Operation throttles implement fine-grained usage agreements.

−	Technical throttles protect service interfaces.

Throttle Calculation

Global Throttle Manager calculates the throttles as follows:

For Quota and High-Water-Mark throttles, it uses the following formula to get the max count per engine:

MaxCountPerEngine = ThrottleMaxCount/maxActiveEngines

For Rate and Error throttles, the calculation is done as follows:

MaxCountPerEngine = (ThrottleMaxCount/maxActiveEngines)*(UpdateIntervalSec/Throttle Interval)

−	ThrottleMaxCount and Throttle Interval are defined in the throttle configuration.

−	UpdateIntervalSec is the time interval in seconds for sending throttle updates to Global Throttle Manager. The default value is 10 seconds and can be edited in the ASG_CONFIG_HOME/asg.properties file. This is defined by the following property:

      tibco.clientVar.ASG/Throttle/UpdateIntervalSec=10

The value of MaxCountPerEngine is always rounded up. For example, 1.1 will be 2 and 1.9 will also be 2.

For non zero throttles, this rounding means that the MaxCount Per Engine will always be at least 1. For example, if there are 20 active engines and the calculated value of MaxCountPerEngine is 0.4, then the effective throttle limit is calculated as:

Ceiling(0.4)*active engines = 1*20 = 20

For this case, the value of MaxCountPerEngine is not 8. (0.4 * 20)

This indicates that if there are many active engines and the throttles are defined in this setup, then the MaxCount can never be less than the number of active engines.

Run Global Throttle Manager

This section explains the steps to run the Global Throttle Manager.

1.	Open a terminal window.

2.	Navigate to ASG_HOME/bin directory.

3.	Type the following command:

   asg-engine -u asg-gtm -a ASG_Configuration_Name

where ASG_Configuration_Name is the project configuration of the API Exchange Gateway.

For example. if you want to run the Global Throttle Manager for the BookQuery configuration, type the following command:

   asg-engine -u asg-gtm -a BookQuery

where BookQuery is the current configuration.

• Make sure that the Cache Agent and the Core Engine are running before you start the Global Throttle Manager. • Type the following command to run the Global Throttle Manager:    asg-engine -u asg-gtm -a ASG_Configuration_Name -n        Global_Throttle_Manager_Instance_Name where ASG_Configuration_Name is the project configuration of the API Exchange Gateway and Global_Throttle_Manager_Instance_Name is the name of the Global Throttle Manager instance.

 

Copyright © Cloud Software Group, Inc. All Rights Reserved