What determines whether a database is suitable for a production environment is not the fancy buzzwords in marketing brochures; it is the locking mechanisms on the disk, its stability in memory management, and its behavior under concurrent requests. For years, we have heard the rote memorization of "SQLite is only for testing, you must use PostgreSQL in production." However, the truth of the matter lies in making decisions by knowing the limits and architectural approaches of both databases. As someone who has pushed both databases to their limits in my own side projects and in the systems I manage in the field, I want to dissect the real-world production performance, advantages, and critical thresholds where these two beasts might let you down. In this article, we will steer clear of theoretical definitions and focus directly on disk blocks, lock logs, RAM consumption, and operational costs.…