Max Ack Pending per Subject?

[praveenperera]

I have a consumer that listens to a stream on subjects client.node.*

Each node sends messages to the subject with its node id. So node id a would be client.node.a

I would like to set max ack pending for each node’s messages to 1 so I can process the messages of each individual node in order.

But I want to process nodes a,b and c’s messages in parallel to each other. Hope that makes sense.

Can I do that with one consumer? Or do I need to make a different consumer for each node?

[Jarema]

Right now it is unfortunately not possible to set max ack pending per subject.
In your use case, you need to create consumer per node, as having max ack pending above 1 can cause out of order redeliveries on not acked messages (missed acks, network issues, etc).

[praveenperera]

Thanks, is this something that would be possible in the future? On the roadmap?

[praveenperera]

@Jarema could I submit this as a feature request? This would help me out a lot.

I don’t have a good way of creating a consumer for each node because new nodes in this system are constantly being created and destroyed.

Best alternative I have is to hash the node id into buckets and make a consumer for each bucket.

[Jarema]

Sure, we can discuss it and see how it would affect the system.

[praveenperera]

Thank you!