Introducing Axon Server 2024.1

We’re excited to introduce Axon Server 2024.1, packed with new updates and features to enhance your development experience. The highlight of this release? Persistent streams.

Let’s dive into how this feature can solve common challenges and streamline your workflow. 

Persistent streams: Your Solution for Efficient Event Handling

1. Easy Subscription and Acknowledgment: When a client subscribes, Axon Server sends events to the client. After processing, the client sends an acknowledgment back. If the client reconnects, it resumes from the last acknowledged event.
   
   
2. Dynamic Segmentation: Persistent streams can be divided into segments, allowing parallel event processing. Segments can be dynamically reassigned across multiple clients to optimize load distribution.  A persistent stream can be split into several segments. This allows for parallel event processing as segments can be distributed across multiple clients. Axon Server provides multiple options for assigning events to specific segments. The number of segments can be changed dynamically.
   
   
3. Event Filtering: Clients can define filters to receive only relevant events before implementing a persistent stream, reducing unnecessary processing and network usage. Clients can provide a filter when they define a persistent stream.

Persistent streams fully integrate with Axon Framework 4.10, making it easy to implement them alongside tracking or pooled streaming event processors. Key benefits include:

• No position tracking: Applications don’t need to manage their position in the event stream, simplifying the process when multiple consumers are involved in a stream.
•  Database-free token management: Axon Framework applications can now skip additional databases for token stores.
• Efficient segment distribution: Segments are dynamically distributed across the connected clients—no more unclaimed segments. 
• Centralized overview: Axon Server provides a centralized view of all the persistent streams and their clients.
• Reduced resource usage: By filtering events server-side, network and CPU usage on the client side are minimized.
  
  

Key Differences from Traditional Event Streams

Persistent streams offer several improvements over existing event streaming functionality:

• Automatic position handling: Clients start receiving events from the last acknowledged position without specifying where to start.
• Segment-specific events: Clients receive only the events for their assigned segments.
• Filtered event delivery: Clients only get events that match their filter conditions.  
• Resource efficiency: Clients don’t need to poll token store tables, reducing database connections and CPU usage.

Conclusion

Axon Server 2024.1’s persistent streams provide a streamlined, infrastructure-free way to handle events. They simplify parallel processing with multiple clients and reduce the overhead typically associated with event tracking and database management.

The new persistent streams feature in Axon Server provides an easy way to subscribe to events in the event store without requiring additional infrastructure on the client side. It makes it easy to process events in parallel with multiple client instances.

For more details, the download and release notes are here.