[gricardo99]

so true. Either you have lots of experience working with specific databases to setup/optimize queries, and you know what works best through personal blood, sweat and tears, and/or you have intimate knowledge of the inner workings of the database architecture/implementation and know the theoretical best approach to structure your schema/queries.

But even then, hardware/networking performance and tuning can throw a wrench in the most seasoned/knowledgeable approaches. Users can further bring otherwise solid setups to a grinding halt with unanticipated use-cases.

The only hope when you hit these inevitable road-blocks is that you're working for someone that appreciates the difficulty of the problem.