Another thing I’ve seen (perhaps even been guilty of :) is assuming we don’t have to worry about our table or index structure. Inserting 10 million narrow rows

Another thing I’ve seen (perhaps even been guilty of :) is assuming we don’t have to worry about our table or index structure. Inserting 10 million narrow rows of integers and enums into a database with just a Pkey index will be super fast. Inserting 10mm wide rows containing json blobs and long text strings will be bad. Inserting 10mm json blobs with a bunch of indexes will be horrible. I’ve been as guilty as anyone for thinking the database can work miracles and that I don’t have to worry about how the underlying hardware works. But it’s that lack of care that is at fault, not the database engine. It’s just doing what you told it to do.