N+1 Prevention:

Used EntityGraph for eager loading when necessary

DTO projections to select only required fields

Batch size configuration in application.properties

Caching Strategy:

Redis cache for frequent role-based queries

Cache eviction on write operations

Time-to-live configuration for cache entries

Transaction Management:

Separate transaction managers for different datasources

Read-only transactions for query operations

Chained transaction manager for cross-database operations

Logging & Monitoring:

Structured logging with MDC

Kafka integration for event tracking

Health checks for all data sources