Replace entity-based queries with DTO-based queries using QueryDSL projections. This addresses performance and lazy loading issues. The new approach uses Projections.constructor() to map query results directly to DTOs (ServiceTrailDto, ServiceTrailHopDto), avoiding eager loading of entities and slow views like FN_DETAILED_OSP_CONNECTION_V. A key change is that the refactored code no longer relies on the slow database views (FN_DETAILED_OSP_CONNECTION_V and FN_OSP_CONNECTION_VIEW) and instead queries the OspConnection entity directly from the base table, significantly improving query performance. Batch fetching was implemented to load hops and OSP connections in single queries instead of N+1 patterns, reducing database round trips from hundreds to 3–4 queries per request.