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JMS Connection Factory: Configuration: Flow Control

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Flow control allows you to enable a JMS server or destination to slow down message producers when it determines that it is becoming overloaded. Specifically, when a JMS server/destination exceeds its specified bytes or messages thresholds, it instructs producers to limit their message flow (messages per second).

Use this page allows to define the flow control configuration for this JMS connection factory.

Configuration Options

Name Description
Flow Maximum

The maximum number of messages-per-second allowed for a producer that is experiencing a threshold condition. When a producer is flow controlled it will never be allowed to go faster than the FlowMaximum messages per second.

If a producer is not currently limiting its flow when a threshold condition is reached, the initial flow limit for that producer is set to FlowMaximum. If a producer is already limiting its flow when a threshold condition is reached (the flow limit is less than FlowMaximum), then the producer will continue at its current flow limit until the next time the flow is evaluated.

Note: Once a threshold condition has subsided, the producer is not permitted to ignore its flow limit. If its flow limit is less than the FlowMaximum, then the producer must gradually increase its flow to the FlowMaximum each time the flow is evaluated. When the producer finally reaches the FlowMaximum, it can then ignore its flow limit and send without limiting its flow.

MBean Attribute (Does not apply to application modules):
FlowControlParamsBean.FlowMaximum

Minimum value: 1

Maximum value: 2147483647

Flow Minimum

The minimum number of messages-per-second allowed for a producer that is experiencing a threshold condition. This is the lower boundary of a producer's flow limit. That is, WebLogic JMS will not further slow down a producer whose message flow limit is at its FlowMinimum.

When a producer is flow controlled it will never be required to go slower than FlowMinimum messages per second.

MBean Attribute (Does not apply to application modules):
FlowControlParamsBean.FlowMinimum

Minimum value: 1

Maximum value: 2147483647

Flow Interval

The adjustment period of time, in seconds, when a producer adjusts its flow from the FlowMaximum number of messages to the FlowMinimum amount, or vice versa.

When a producer is flow controlled, it is slowed down from its FlowMaximum to its FlowMinimum over the specified FlowInterval amount of seconds.

MBean Attribute (Does not apply to application modules):
FlowControlParamsBean.FlowInterval

Minimum value: 0

Maximum value: 2147483647

Flow Steps

The number of steps used when a producer is adjusting its flow from the Flow Maximum amount of messages to the Flow Minimum amount, or vice versa. Specifically, the Flow Interval adjustment period is divided into the number of Flow Steps (for example, 60 seconds divided by 6 steps is 10 seconds per step).

Also, the movement (i.e., the rate of adjustment) is calculated by dividing the difference between the Flow Maximum and the Flow Minimum into steps. At each Flow Step, the flow is adjusted upward or downward, as necessary, based on the current conditions, as follows:

  • The downward movement (the decay) is geometric over the specified period of time (Flow Interval) and according to the specified number of Flow Steps. (For example, 100, 50, 25, 12.5)

  • The movement upward is linear. The difference is simply divided by the number of steps.

MBean Attribute (Does not apply to application modules):
FlowControlParamsBean.FlowSteps

Minimum value: 1

Maximum value: 2147483647

Flow Control Enabled

Specifies whether a producer created using a connection factory allows flow control. If true, the associated message producers will be slowed down if a JMS server or a destination reaches its specified upper byte or message threshol.

MBean Attribute (Does not apply to application modules):
FlowControlParamsBean.FlowControlEnabled

Send Timeout

The maximum length of time, in milliseconds, that a sender will wait when there isn't enough available space (no quota) on a destination to accommodate the message being sent.

The default time is 10 milliseconds. A value of 0 indicates that the sender does not want to wait for space.

This attribute is dynamic. It can be changed at any time. However, changing the value does not affect existing connections or their producers. It only affects new connections made with this connection factory. Producers inherit the setting from the connection factory used to create their session and connection. The value can then be overridden at run time by setting the value on the producer.

MBean Attribute (Does not apply to application modules):
DefaultDeliveryParamsBean.SendTimeout

Minimum value: 0

Maximum value: 9223372036854775807

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