Advanced Caching Architecture

Reconstituting an aggregate state from a long stream of events can be costly if done for every command or read request. Sharpino implements an advanced, multi-tiered caching architecture to handle this, ensuring both blazing-fast reads and strict consistency across distributed nodes.

The Refreshable Details Cache

Detail views are implemented using a Refreshable<'A> or RefreshableAsync<'A> interface. Because they depend on Aggregate states, Sharpino tracks these dependencies. The Detail Cache received a massive boost by utilizing async, task-based refreshable details.

When an Aggregate produces a new event, the system immediately and asynchronously triggers a refresh (RefreshDependentDetails) on all Details that depend on that specific Aggregate ID. This ensures the high-performance read models never drift from the Event Store.

L1, L2, and the Message Backplane

To support horizontal scaling, Sharpino instruments its cache layers with an L2 Cache and a Message Backplane.

  • L1 Cache (In-Memory): A localized, ultra-fast cache holding reconstructed Aggregates and active Detail closures.
  • L2 Cache (SQL/Azure SQL): A distributed cache layer that shares easily serialized data across nodes.
  • Message Backplane: To prevent nodes from serving stale L1 data, Sharpino uses a backplane (Azure Service Bus or MQTT). When Node A updates an aggregate, it broadcasts an invalidation message over the backplane. Node B receives this, instantly invalidates its stale L1 cache, and automatically triggers its local RefreshDependentDetails process.

Synchronization Flow

graph TD
    subgraph Node_A_Writer
        A_App[App Command] --> A_AC[AggregateCache3]
        A_AC --> A_EventStore[Database / EventStore]
        A_AC -. "1. Update Local" .-> A_L1[L1 Cache]
        A_AC -- "2. Publish Message" --> ASB((Azure Service Bus / MQTT<br/>Backplane))
    end

    subgraph Node_B_Reader
        ASB -- "3. Receive Message" --> B_AC[AggregateCache3]
        B_AC -. "4. Invalidate/Remove" .-> B_L1_Agg[Aggregate L1 Cache]
        B_AC -- "5. Trigger Refresh" --> B_DC[DetailsCache]
        B_DC -. "6. Recompute View" .-> B_L1_Det[statesDetails L1 Cache]
    end

    subgraph External
        L2[(Azure SQL L2 Cache)]
        A_AC -. "Optional Sync" .-> L2
        B_AC -. "Optional Request" .-> L2
    end