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Payload Size Throttles

Using TIBCO API Exchange Gateway, you can create throttles based on the size of a payload in the message. For payload size throttles, the throttle count for a throttle is incremented as per the size of the payload in the message.

For the rate and quota throttle types, define the throttles based on the payload size as follows:

•	Payload size in the request message.

•	Payload size in the response message.

•	Payload size in both request and response message.

For the payload size throttles, define a throttle counter to specify the message type for which the payload size is calculated. For example, if the throttle counter is defined as Input Payload Size, the throttle count is incremented by the payload size of the request message. The throttle count is incremented by the payload size of the response message if the throttle counter is defined as Output Payload Size.

• The throttle Max Count for a payload size throttle should be specified in bytes. • The payload size value in a message is used as an increment counter for the throttle count. The throttle counter field determines if the payload size is calculated for the request message, response message, or both request and response message. • The payload size throttles are not supported for the Error and High Water Mark (HWM) throttle types.

Payload Size Throttle Types

Based on the throttle counter value, the payload size throttles can be any of the following subtypes:

•	Input Payload Size

Specifies that the throttle count for a throttle is incremented by the size of the input message (that is, request message).

•	Output Payload Size

Specifies that the throttle count for a throttle is incremented by the size of the output message (that is, response message).

•	Transaction Payload Size

Specifies that the throttle count for a throttle is incremented by the sum of the size of input and output message (that is, request and response payload).

For example, you can define a payload size throttle T2 as follows:

---

 

Throttle Name: T2

Throttle Type : Rate

Throttle Interval : 10 seconds

Throttle Max Count: 10000

Throttle Counter: Input Payload Size

---

 

For this throttle T2 configuration, the Core Engine allows 10000 bytes of request payload size in 10 seconds. For instance, if the first incoming request has a payload size of 5000 bytes, the Core Engine performs the following actions:

•	Checks the current throttle count, which is 0 bytes as this is the first request.

•	Compares if the current throttle count (0 bytes) is less than or equal to the throttle max count (10000 bytes).

•	Increments the current throttle count value by 5000 bytes, so the value of throttle count becomes 5000 bytes.

•	Checks if the current throttle count (5000 bytes) is less than or equal to the throttle max count (10000 bytes).

•	Forwards the request to the back-end service for processing as the throttle count is less than max count.

If the second request received after 3 seconds has a payload size of 5000 bytes, the Core Engine performs the following actions:

•	Checks the current throttle count, which is 5000 bytes.

•	Compares if the current throttle count (5000 bytes) is less than or equal to the throttle max count (10000 bytes).

•	Increments the current throttle count value by 5000 bytes, so the value of throttle count becomes 10000 bytes.

•	Checks if the current throttle count (10000 bytes) is less than or equal to the throttle max count (10000 bytes).

•	Forwards the request to the back-end service for processing as the throttle count(10000) is less than the max count (10000).

If the third request received after 2 seconds has a payload size of 1000 bytes, the Core Engine performs the following actions:

•	Checks the current throttle count, which is 10000 bytes.

•	Compares if the current throttle count (10000 bytes) is less than or equal to the throttle max count (10000 bytes).

•	Increments the current throttle count value by 5000 bytes, so the value of throttle count becomes 15000 bytes.

•	Checks if the current throttle count (15000 bytes) is less than or equal to the throttle max count (10000 bytes).

•	Rejects the request for processing as the throttle count(15000) reached the max count (10000). The Core Engine sends an error back to the client.

Configuring Payload Size Throttles

The payload size throttles are configured using the Config UI. You can configure the throttles for the payload size of request, response, or both request and response messages.

To configure the payload size throttles, follow these steps:

1.	Start the GUI server, if not already running.

2.	Log in to the Config UI using your credentials.

3.	Add a new configuration or select an existing configuration.

4.	Click the MONITORING tab on the right hand side.

5.	Click the Monitors tab.

6.	Specify the following parameters:.

Table 92 Payload Size Throttle

Parameter	Description
Monitor Name	• Specifies the name of the throttle. For example, T2 • Required.
Monitor Type	• Specifies the type of throttle. Select one of the possible values from the drop-down list for the payload size throttle: − Rate − Quota • Required. • Example, Rate
Interval	Specifies a time period for which the maximum count of throttles are allowed.
Max Limit	Specifies the maximum number of throttle count allowed during the throttle interval period.
Monitor Counter	Specifies the message type for which the payload size is calculated. Select one of the possible values from the drop-down list: − Input Payload Size − Output Payload Size − Transaction Payload Size

Configure Payload Size Throttle for Request Message

To configure the payload size throttle for a request message, configure the Throttle Counter as Input Payload Size for a throttle configuration.

Configure Payload Size Throttle for Response Message

To configure the payload size throttle for a response message, configure the Throttle Counter as Output Payload Size for a throttle configuration.

Configure Payload Size Throttle for Request and Response Message

To configure the payload size throttle for both the request and response message, configure the Throttle Counter as Transaction Payload Size for a throttle configuration.

If an XSLT is configured to define content based throttle using metricName and metricIncrement for a throttle which also has payload based throttle configured, the Core Engine applies the content based throttle policy at run time.

 

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