graph TB subgraph "Foundation.ProcessRegistry Module (1,143 lines)" API[Public API Layer] API --> |"register/4"| RegFunc[register function] API --> |"lookup/2"| LookFunc[lookup function] API --> |"unregister/2"| UnregFunc[unregister function] API --> |"via_tuple/2"| ViaFunc[via_tuple function] RegFunc --> |"ensure_backup_registry()"| EnsureETS[ETS Table Creation] EnsureETS --> |":ets.new(:process_registry_backup)"| ETSTable[(ETS Backup Table)] RegFunc --> |"lines 140-193"| CustomLogic[Custom Registry+ETS Logic] CustomLogic --> |":ets.lookup/insert"| ETSTable CustomLogic --> |"Registry operations"| NativeReg[Native Registry] LookFunc --> |"Registry.lookup first"| NativeReg LookFunc --> |"fallback to ETS"| ETSTable UnregFunc --> |"Registry.unregister"| NativeReg UnregFunc --> |":ets.delete"| ETSTable ViaFunc --> |"via tuple creation"| NativeReg end subgraph "Optimization Module (lines 996-1127)" OptAPI[Optimization Functions] OptAPI --> |"register_with_indexing/4"| OptReg[Optimized Register] OptAPI --> |"cached_lookup/2"| OptLook[Cached Lookup] OptAPI --> |"bulk_register/1"| BulkReg[Bulk Operations] OptReg --> |"bypasses backend"| OptModule[Foundation.ProcessRegistry.Optimizations] OptLook --> OptModule BulkReg --> OptModule end subgraph "UNUSED Backend System (258 lines + implementations)" BackendBeh[Backend Behaviour] BackendBeh -.-> |"@callback init/1"| InitCB[init callback] BackendBeh -.-> |"@callback register/4"| RegCB[register callback] BackendBeh -.-> |"@callback lookup/2"| LookCB[lookup callback] BackendBeh -.-> |"@callback unregister/2"| UnregCB[unregister callback] BackendBeh -.-> |"@callback list_all/1"| ListCB[list_all callback] BackendBeh -.-> |"@callback update_metadata/3"| UpdateCB[update_metadata callback] BackendBeh -.-> |"@callback health_check/1"| HealthCB[health_check callback] ETSBackend[ETS Backend - 387 lines] ETSBackend -.-> |"implements all callbacks"| BackendBeh ETSBackend -.-> |"performance optimizations"| ETSPerfOpt[Dead Process Cleanup
Statistics Collection
Memory Tracking] RegBackend[Registry Backend] RegBackend -.-> BackendBeh HordeBackend[Horde Backend - Distributed] HordeBackend -.-> BackendBeh HordeBackend -.-> |"cluster coordination"| DistFeatures[Distributed Features
Node Failover
Global Registry] end subgraph "Configuration System (UNUSED)" ConfigSys[Backend Configuration] ConfigSys -.-> |"backend selection"| BackendSelect[Runtime Backend Selection] ConfigSys -.-> |"backend_opts"| BackendOpts[Backend Options] BackendSelect -.-> ETSBackend BackendSelect -.-> RegBackend BackendSelect -.-> HordeBackend end %% No connections between main module and backend system! %% Problems highlighted ETSTable ==> |"REDUNDANT STORAGE"| BackendBeh CustomLogic ==> |"BYPASSES ABSTRACTION"| BackendBeh OptModule ==> |"IGNORES BACKEND SYSTEM"| BackendBeh %% Styling classDef used fill:#ccffcc,stroke:#00aa00,stroke-width:3px classDef unused fill:#ffcccc,stroke:#aa0000,stroke-width:3px,stroke-dasharray: 10 10 classDef problem fill:#ffaaaa,stroke:#ff0000,stroke-width:4px class API,RegFunc,LookFunc,UnregFunc,ViaFunc,CustomLogic,NativeReg,ETSTable,OptAPI,OptModule used class BackendBeh,ETSBackend,RegBackend,HordeBackend,ConfigSys,BackendSelect,InitCB,RegCB,LookCB,UnregCB,ListCB,UpdateCB,HealthCB,ETSPerfOpt,DistFeatures,BackendOpts unused class CustomLogic,ETSTable,OptModule problem

graph TB subgraph "ProcessRegistry API (Simplified)" API[Public API Layer] API --> |"register/4"| GenServerCall[GenServer.call] API --> |"lookup/2"| GenServerCall API --> |"unregister/2"| GenServerCall API --> |"via_tuple/2"| ViaHelper[Via Tuple Helper] end subgraph "ProcessRegistry GenServer" GenServerCall --> |"handle_call"| CallHandlers[Handle Call Functions] CallHandlers --> |"{:register, key, pid, meta}"| RegHandler[Register Handler] CallHandlers --> |"{:lookup, key}"| LookHandler[Lookup Handler] CallHandlers --> |"{:unregister, key}"| UnregHandler[Unregister Handler] RegHandler --> |"backend.register(state, key, pid, meta)"| BackendCall[Backend Delegation] LookHandler --> |"backend.lookup(state, key)"| BackendCall UnregHandler --> |"backend.unregister(state, key)"| BackendCall BackendCall --> |"update backend_state"| StateUpdate[State Management] StateUpdate --> |"new backend_state"| GenServerState[GenServer State] end subgraph "Backend Configuration System" AppConfig[Application Config] AppConfig --> |"backend: ETS/Registry/Horde"| BackendSelector[Backend Selection] AppConfig --> |"backend_opts: [...]"| BackendOpts[Backend Options] BackendSelector --> |"init(opts)"| BackendInit[Backend Initialization] BackendInit --> |"returns backend_state"| InitialState[Initial Backend State] InitialState --> GenServerState end subgraph "Backend Implementations" BackendCall --> |"runtime delegation"| BackendInterface[Backend Interface] BackendInterface --> |"configured backend"| SelectedBackend{Selected Backend} SelectedBackend --> |"local storage"| ETSBackend[ETS Backend] SelectedBackend --> |"native registry"| RegBackend[Registry Backend] SelectedBackend --> |"distributed"| HordeBackend[Horde Backend] ETSBackend --> ETSStorage[(ETS Table)] ETSBackend --> |"dead process cleanup"| ETSCleanup[Automatic Cleanup] ETSBackend --> |"health monitoring"| ETSHealth[Health Checks] ETSStorage --> |"O(1) operations"| ETSPerf[High Performance
< 1ms latency
Concurrent access] RegBackend --> RegStorage[Native Registry] RegBackend --> |"OTP supervision"| RegSupervision[Automatic Process Monitoring] RegStorage --> |"partitioned storage"| RegPerf[CPU Optimized
Automatic cleanup
Fault tolerance] HordeBackend --> DistStorage[Distributed Registry] HordeBackend --> |"node coordination"| NodeSync[Node Synchronization] DistStorage --> |"cluster operations"| DistPerf[Global Consistency
Node failover
Network partition handling] end subgraph "Optimization Layer" OptimizationAPI[Optimization Functions] OptimizationAPI --> |"register_with_indexing/4"| OptReg[Enhanced Register] OptimizationAPI --> |"cached_lookup/2"| OptLook[Cached Lookup] OptReg --> |"first register normally"| BackendCall OptReg --> |"then add indexing"| IndexSystem[Metadata Indexing] OptLook --> |"check cache first"| CacheLayer[Cache Layer] CacheLayer --> |"cache miss"| BackendCall CacheLayer --> |"cache hit"| CacheHit[Direct Return] IndexSystem --> |"ETS metadata index"| MetaIndex[(Metadata Index Table)] MetaIndex --> |"fast searches"| FastSearch[O(1) metadata queries] end subgraph "Monitoring & Health" HealthAPI[Health Check API] HealthAPI --> |"get_stats/0"| StatsCall[Statistics Call] StatsCall --> |"backend.health_check(state)"| BackendHealth[Backend Health Check] BackendHealth --> |"backend-specific metrics"| HealthMetrics[Health Metrics] HealthMetrics --> |"registration count"| RegCount[Registration Count] HealthMetrics --> |"memory usage"| MemUsage[Memory Usage] HealthMetrics --> |"performance stats"| PerfStats[Performance Statistics] HealthMetrics --> |"error rates"| ErrorRates[Error Rates] end %% Runtime backend switching capability BackendSelector -.-> |"runtime reconfiguration"| RuntimeSwitch[Runtime Backend Switching] RuntimeSwitch -.-> |"migrate state"| StateMigration[State Migration] StateMigration -.-> SelectedBackend %% Styling classDef api fill:#e6f3ff,stroke:#0066cc,stroke-width:2px classDef genserver fill:#f0f8e6,stroke:#2d5a27,stroke-width:2px classDef backend fill:#fff2e6,stroke:#cc6600,stroke-width:2px classDef storage fill:#f8f0ff,stroke:#6600cc,stroke-width:2px classDef optimization fill:#ffe6f0,stroke:#cc0066,stroke-width:2px classDef monitoring fill:#f0fff0,stroke:#006600,stroke-width:2px class API,GenServerCall,ViaHelper api class CallHandlers,RegHandler,LookHandler,UnregHandler,BackendCall,StateUpdate,GenServerState genserver class AppConfig,BackendSelector,BackendOpts,BackendInit,BackendInterface,SelectedBackend,ETSBackend,RegBackend,HordeBackend backend class ETSStorage,RegStorage,DistStorage,MetaIndex storage class OptimizationAPI,OptReg,OptLook,CacheLayer,IndexSystem,FastSearch optimization class HealthAPI,StatsCall,BackendHealth,HealthMetrics monitoring

# Development - Fast local storage
config :foundation, ProcessRegistry,
  backend: Foundation.ProcessRegistry.Backend.ETS,
  backend_opts: [cleanup_interval: 30_000]

# Production - Distributed cluster
config :foundation, ProcessRegistry,  
  backend: Foundation.ProcessRegistry.Backend.Horde,
  backend_opts: [
    members: [:node1@host, :node2@host, :node3@host],
    sync_interval: 5_000
  ]