Good notes posted by cowlibob

Beware - May cause performance issues

A serialized attribute will always be updated during save, even if it was not changed. (A rails 3 commit explains why: http://github.com/rails/rails/issues/8328#issuecomment-10756812)

Guard save calls with a changed? check to prevent issues.

class Product < ActiveRecord::Base
  serialize :product_data
end

bad

product = Product.first
product.save

good

product = Product.first
product.save if product.changed?