Slow Database Queries on Replit

1. Missing database indexes on frequently queried columns
2. N+1 query problem (fetching parent then looping child queries)
3. SELECT * instead of specific columns
4. No query pagination (fetching 1M rows at once)
5. Complex joins without optimization

Enable query logging to identify slow queries. Add indexes to WHERE clause columns. Use eager loading (JPA @EntityGraph or Hibernate batch fetch) to prevent N+1. Implement pagination and limit result sets. Use database EXPLAIN ANALYZE to optimize queries.