So, I have a table with about 2.4M rows and ~30 columns. There is no unique column within the data. The data is transaction logs from stores where each transaction number is only unique on a per store basis and resets at midnight, but that's besides the point.
As it stands, queries on this table take upwards of one minute and I can't figure out why. I have added indexes on columns that have high selectivity ratio but it hasn't made any difference. So, if I add an auto increment 'id' field for each row, would that speed things up, or are the queries slow because there are so many columns and so much unique data?