Using Postgres cursors to iterate through a table

gistfile1.rb

class YrModel < ActiveRecord::Base
  has_many :derps
  def self.find_with_cursor(query, &blk)
    cursor_name = "cursor_#{(rand * 1000000).ceil}"
    self.transaction do
      self.connection.execute("DECLARE #{cursor_name} CURSOR FOR #{query.to_sql}")
      while !(records = self.find_by_sql("FETCH FORWARD 1000 FROM #{cursor_name}")).empty?
        #FIXME I think this method is deprecated in 3.1 in favor of #preload
        preload_associations(records, [:derps])
        blk.call(records)
      end
    end
  end
end