I currently have a table which contains a VARCHAR(20) column. The assumption that the column will contain a maximum of 20 characters has held for a long time, however recently a need has resulted for it to also contain very long strings. Is there a performance overhead on the table on (i.e inserts/deletes/selects) if I were to change the table to smalltext (or a long varchar). I never need to search on this field, just retrieve and insert it's value. If so, should I (reluctantly) introduce a separate column for the larger values?
Thanks a million