I've got a table with about two and a half million records in. One of the columns in the table is ipAddress which seems to be stored as a varchar(50). why I did that I do not know!
I understand that alter table will make a copy of the entire table. So if I changed the field to a varchar(15) it'd have a massive CPU and disk usage issue. How about if I just changed the index to length 15? Would that have to copy the whole table, or just that one index? And would using this shorter key improve efficiency?
I know it's more efficient to store ip addresses as unsigned ints, but I don't want to have to change too much right now if I don't have to.