Kafka consumer throughput. Usage of KafkaMessageBusOptions.DefaultConsumerThreadCount

[jojopeter]

Hi,
This is a query on Consumer throughput of Kafka when I use Foundatio my application.

We subscribe to the messages in following manner.

namespace : Foundatio.Messaging
class : static class MessageBusExtensions
Method:
public static Task SubscribeAsync(this IMessageSubscriber subscriber, Func<T, Task> handler, CancellationToken cancellationToken = default) where T : class {
return subscriber.SubscribeAsync((msg, token) => handler(msg), cancellationToken);
}

We are using above method and the implementation is as follows

      messageBus.SubscribeAsync<message>(
       m => this.HandleMessageAsync(m)).GetAwaiter().GetResult();

      var options = new KafkaMessageBusOptions
      {
        DefaultConsumerThreadCount = 4,
        ManualCommitBatch = 10,
        ProducerConfig = new ProducerConfig
        {
          BootstrapServers = bootstrapServers,
          Acks = Acks.Leader,
          Partitioner = Partitioner.ConsistentRandom,
          SecurityProtocol = securityProtocol,
          Debug = "security"
        },
        ConsumerConfig = new ConsumerConfig
        {
          GroupId = consumerGroupId,
          BootstrapServers = bootstrapServers,
          AutoOffsetReset = AutoOffsetReset.Latest,
          EnableAutoCommit = true,
          AutoCommitIntervalMs = 5000,
          CancellationDelayMaxMs = 1000,
          SessionTimeoutMs = 100000,
          SecurityProtocol = securityProtocol,
          Debug = "security"
        }
      };
      services.AddFoundatioKafkaMessageBus(options);

We noticed the consumer throughput is very low and trying to optimize it. As part of this I changed the DefaultConsumerThreadCount from 4 to 8. But that didn't make any difference to the consumer throughput.
Can you please let us know what is the intention of 'DefaultConsumerThreadCount'? Is there any other setting I can change to increate the consumer throughput?

Thanks In advance,
Jojo Peter

[niemyjski]

We don't have a Kafka message bus implementation that we ship with. What NuGet package are you using? We also try not to do any GetAwaiter().GetResults() in an async code path.

[jojopeter]

Thanks for your reply.
Sorry I posted in the repository.
BTW, I am using 'Aix.KafkaMessageBus' package.

Thanks.

[niemyjski]

No problem, I'm going to close this as we don't own that code. I'd recommend posting on their project repository. If you have any feedback on the core libraries we would love to hear it.