Re: LOW_PRIORIY, IGNORE, DELAY & QUICK

[Rick James]

Most of those are not effective because commands happen too fast to have any conflicts. Not bother using them. Except...

This one,
INSERT IGNORE ...;
on the other hand, has some use. Suppose you want to insert a row, but it might already be there. A plain INSERT would give you an error. INSERT IGNORE would say "oh, that UNIQUE/PRIMARY key already exists, I will silently do nothing". (See also REPLACE, which first DELETEs the row, then INSERTs it.)