What are the most common challenges in scaling SQL databases for startups?

Scaling SQL databases for startups presents challenges in terms of query load management, data consistency, and performance bottlenecks due to inefficient indexing or poorly optimized queries. Vertical scaling will get very expensive fast, while horizontal scaling by sharding adds great complexity to both data management and application logic. Other challenges involve maintaining high performance with large data sets and ensuring high availability. Startups must balance scalability with budgetary constraints. Such issues need resolution that involves scalable architectures, query optimization, and monitoring tools.