so many problems with its internal design that hide problems until its too late I always got the impression (since I started using it in Prod in the late 90s)

so many problems with its internal design that hide problems until its too late I always got the impression (since I started using it in Prod in the late 90s) that the MySQL team had never worked on an RDBMS before, even as users, and didn't really understand it. Back then they would say, you don't need foreign keys, you can just enforce consistency in your application, you don't need transactions, you can just handle it in your application, and so on and so on. Monty Widenius was very arrogant and thought he knew everything. Eventually they matured a bit and realized that actually, yes, the entire rest of the database community weren't idiots, maybe there is something to these features, but now they needed to find a way to retro-fit them onto what they had and now - 20 years later - they still haven't figured out how to smush it into their architecture. Whereas the Postgres crew were fresh out of the Ingres project led by the genius Michael Stonebraker, they had a solid foundation and very clear vision and a culture of doing the right thing, not the easy thing. There's a steeper learning curve to Postgres but once you have learned a few things you can easily guess the rest because it's so consistent. For MySQL you really need a "guru" because there are so many dark corners and weird edge cases that make no sense, you just have to "know" them.