Adding an index means the write path suddenly became slower. Sometimes, a covering index will be very beneficial. « It depends » is usually the right answer. I’

Adding an index means the write path suddenly became slower. Sometimes, a covering index will be very beneficial. « It depends » is usually the right answer. I’m fine with the engine telling me « this query is usually slow » and I investigate why. I’m not ok with the engine adding indices willy-nilly and suddenly writing to the DB is 10x slower.