Let's see how histograms work for CHAR columns
Now, put a breakpoint in Field:os_in_interval_val_str and run:
So, mp < minp < maxp . This is expected. Now , run this line
We use unsigned substraction, and end up with the wrong value_position number. The return value of Field:os_in_interval_val_str() is 1 although it should have been 0.