Random Pagination

Sometimes you want to display records in a random order, but also paginate them.

order("RANDOM()") can return duplicates on next pages.

My solution is to set a random seed, and then order by a random value set with that seed.

  def index
    cookies[:seed] ||= SecureRandom.random_number
    @posts = Post.order(Arel.sql("random()")).from("(SELECT setseed(#{cookies[:seed]})) as seed_setup, posts")
    @pagy, @posts = pagy_countless(@posts, items: 24)
  end

This will return a random order of posts, and the same order on each page.