sequenceDiagram
    participant User
    participant LeaderRegion as Leader Region (HTTP Handler)
    participant Querier1 as Querier (Region 1)
    participant Querier2 as Querier (Region 2)
    participant LocalStorage as Local Storage
    participant RemoteRegion as Remote Region (gRPC)
    
    User->>LeaderRegion: POST /api/{org}/prometheus/api/v1/query_range
    Note over User,LeaderRegion: Query params: query, start, end, step, regions, clusters
    
    LeaderRegion->>LeaderRegion: Parse parameters and check super_cluster enabled
    LeaderRegion->>LeaderRegion: Partition time range by querier count
    
    par Parallel Querier Dispatch
        LeaderRegion->>Querier1: gRPC Metrics.Query (time partition 1)
        LeaderRegion->>Querier2: gRPC Metrics.Query (time partition 2)
    end
    
    par Each Querier Processing
        Querier1->>LocalStorage: Load local region data
        LocalStorage-->>Querier1: Local metrics data
        
        alt Super Cluster Enabled
            Querier1->>RemoteRegion: gRPC Metrics.Data (same time range)
            RemoteRegion->>RemoteRegion: Query metrics from remote region
            RemoteRegion-->>Querier1: Stream metrics data
            Querier1->>Querier1: Merge local + remote data
        end
        
        Querier1->>Querier1: Execute PromQL computation
        Querier1-->>LeaderRegion: Return computed results
        
        Querier2->>LocalStorage: Load local region data
        LocalStorage-->>Querier2: Local metrics data
        
        alt Super Cluster Enabled
            Querier2->>RemoteRegion: gRPC Metrics.Data (same time range)
            RemoteRegion-->>Querier2: Stream metrics data
            Querier2->>Querier2: Merge local + remote data
        end
        
        Querier2->>Querier2: Execute PromQL computation
        Querier2-->>LeaderRegion: Return computed results
    end
    
    LeaderRegion->>LeaderRegion: Merge results from all queriers
    LeaderRegion->>LeaderRegion: Apply final aggregations
    LeaderRegion-->>User: Return final PromQL result