Throttling is used to set the maximum number of concurrent messages that are processed by a particular endpoint. Increased message load and large message payloads can cause memory usage spikes that can decrease performance. Throttling limits resource consumption so that consistent performance is maintained. In most cases, the trigger message from the Scheduler Binding Component is small, and limiting resource consumption is not an issue.
Throttling can also be used to configure serialization, or the order in which messages are processed. When set to a value of 1, then only one trigger message can be processed at a time, guaranteeing that regardless of size, messages are processed in the order in which they fire.
To configure Throttling for a specific endpoint, open the QoS Properties Editor for that endpoint. From the Throttling Extension section of the editor, configure the Maximum Concurrency Limit property. Specify the maximum number of concurrent messages to be processed for this connection, or enter a value of 1 to guarantee serial message processing.