[venantius]

I am not an expert, but I have worked somewhere MariaDB/MySQL was being used at scale.

My preference today for Postgres comes down to the fact that its query planner is much easier to understand and interface with, whereas MySQL/Maria would be fine 29/30 times but would then absolutely fuck you with an awful query plan that you needed a lot of experience with to anticipate.

[evanelias]

On the other hand, at least MySQL/MariaDB has built-in support for index hints. Postgres does not, and you can absolutely still get bitten by unexpected query plan changes. It's rarer than bad plans in MySQL, but it's worse when it happens in pg -- without index hint support, there's no simple built-in solution to avoid this.