Basically,
SELECT title FROM articles WHERE MATCH(title) AGAINST ('abc') is matched under ft_min_word_len=3
but,
SELECT title FROM articles WHERE MATCH(title) AGAINST ('ab') is not matched under ft_min_word_len=3 because ab is just ignored since it is 2 letters.
What I want is that 'ab' to be matched, but all other 2 letter words ignored.