Mysql Incrementing variable performance

Question

I has looking for a way to sort items in a mysql table. Here a simplified version of the table

sqlfiddle => http://sqlfiddle.com/#!2/78521b/3/0

CREATE T         


        

Answer 1

Don't store sort in the table; store it in a separate table. Furthermore, don't UPDATE that table, recreate it. Further-furthermore, use the following to avoid any downtime:

CREATE TABLE New SELECT ... -- generate new sort order
RENAME TABLE Sort TO Old, New To Sort;
DROP TABLE Old;