How to fix We cannot connect to Event Hub partition [0] because the maximum number of allowed receivers per partition in a consumer group has been reached

Question

We cannot connect to Event Hub partition [0] because the maximum number of allowed receivers per partition in a consumer group has been reached. Ensure that other Stream Analytics jobs or Service Bus Explorer are not using the same consumer group. The following information may be helpful in identifying the connected receivers: Exceeded the maximum number of allowed receivers per partition in a consumer group which is 5. List of connected receivers - asa_XYZ, asa_ABC/+TF6Q, asa_DEF, asa_GHI, asa_JKL. TrackingId:2677ffda-1003-4823-9120-27704ca6b33d_B19, SystemTracker:event:eventhub:prod~32766, Timestamp:2025-02-11T00:56:39 Reference:aa14adcd-ef89-436b-bf63-f094a27f9535, TrackingId:5cfc98be-04b9-4611-800b-c422a2030825_B19, SystemTracker:event:eventhub:prod~32766|prod, Timestamp:2025-02-11T00:56:39 TrackingId:1cfc769edb444cb9bdf876ee40d402c4_G9, SystemTracker:gateway5, Timestamp:2025-02-11T00:56:39. For troubleshooting information, see https://aka.ms/azsdk/net/eventhubs/exceptions/troubleshoot

Answer 1

Hello @h85824 ,

thanks for the more elaborate background information.

My first impression is that the EventHub has only a partition count of 1.

Although this is the default setting of an Eventhub when created, the partition count plays a vital role in parallelism and scale.

So this number has to be set conform the overall architecture.

If the partition count is too small, it can become a bottleneck. For example if An IoT Hub is ingesting data from an IoT hub having 4 partitions, it is a common solution to give the event hub also 4 partitions. The same goes for downstream services.

My expectations are that increasing the partition count to eg. 4 could solve your problem. The actual number will probably depend on more factors so please check the documentation.

Using more partitions does not involve extra costs. There are some limitations in the total number of partitions supported but that does not seems to be a problem here.

Unfortunately, the number of partitions is set and fixed after creating an Eventhub. So, you need to recreate the Eventhub and reattach the stream analytics job.

Please let us know if this helps in getting rid of the error messages.

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