Azure Service Bus Trigger Function Not Achieving Desired Concurrency Levels

akalanka sakalasooriya 0 Reputation points

I have implemented a system where requests are processed asynchronously using an Azure Service Bus. These requests initiate an operation that, once complete, returns a response to the initiating actor. My objective is to manage the flow of requests to OpenAI efficiently, particularly by limiting the number of concurrent requests to 8 to prevent token bottlenecks.

I have configured my host.json as follows to achieve this limit:

  "extensions": {
    "serviceBus": {
      "batchOptions": {
        "maxMessageCount": 1,
        "autoComplete": true
      "prefetchCount": 8,
      "messageHandlerOptions": {
        "autoComplete": true,
        "maxConcurrentCalls": 8


Additionally, I have set the environment variables WEBSITE_MAX_DYNAMIC_APPLICATION_SCALE_OUT and FUNCTIONS_WORKER_PROCESS_COUNT to 1.

Despite these configurations and referencing Azure Functions, the Service Bus queue often has many messages, but the actual number of concurrent requests remains low (typically 1 or 2).

Why might the Azure Service Bus Trigger Function not be achieving the expected level of concurrency given these settings? What changes should I consider to ensure the number of concurrent requests consistently reaches the limit of 8?


Azure Functions
Azure Functions
An Azure service that provides an event-driven serverless compute platform.
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