Azure EventHubs "Exceeded the maximum number of allowed receivers per partition"

Question

Azure Eventhubs gives "Exceeded the maximum number of allowed receivers per partition in a consumer group which is 5" (I'm consuming it through a Java application)

That's expected, as I was testing and forgot to call close on consumers. However, there doesn't seem to be a way to expire existing stale consumers.

It's been a few hours now and I can't connect a new consumer, as apparently consumers are stuck there. Is there a way to "unblock" the hub, or the only way to go is deleting it and recreating it?

That wouldn't be ideal, as even when there's proper handling, there's a chance of a process dying mid-consumption, leaving a stale consumer.

Answer 1

Hello @Bozhidar Bozhanov ,

Thanks for the question and using MS Q&A platform.

The expected behavior is that Event Hubs would terminate a 6th receiver.

The number of non-epoch receivers per consumer group is five.

There can be at most 5 concurrent readers on a partition per consumer group; however it's recommended that there's only one active receiver on a partition per consumer group. Within a single partition, each reader receives all of the messages. If you have multiple readers on the same partition, then you process duplicate messages. You need to handle this in your code, which may not be trivial. However, it's a valid approach in some scenarios.

For more details, refer to Azure Event Hubs quotas and limits and Azure Event Hubs - Consumer Groups.

Hope this will help. Please let us know if any further queries.

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