I think we're going to need to make the code handle this by testing whether EXPLAIN shows not only no index chosen, but also a large number of rows (larger than expected). If for some reason it's ignoring the index but there aren't many rows, that should be OK.
I think we're going to need to make the code handle this by testing whether EXPLAIN shows not only no index chosen, but also a large number of rows (larger than expected). If for some reason it's ignoring the index but there aren't many rows, that should be OK.