validate models vs db in an rails app

validate_models.rake

# file: validate_models.rake
# task: rake db:validate_models
namespace :db do
  desc "Run model validations on all model records in database"
  task :validate_models => :environment do
    puts "-- records - model --"
    Dir.glob(Rails.root.join('app/models/**/*.rb')).each { |file| require file }
    ActiveRecord::Base.descendants.select { |c|
          c.base_class == c}.sort_by(&:name).each do |klass|
      total = klass.count
      printf "%10d - %s\n", total, klass.name
      chunk_size = 1000
      (total / chunk_size + 1).times do |i|
        chunk = klass.find(:all, :offset => (i * chunk_size), :limit => chunk_size)
        chunk.reject(&:valid?).each do |record|
          puts "#{record.class}: id=#{record.id}"
          p record.errors.full_messages
          puts
        end rescue nil
      end
    end
  end
end

You might be interested in .find_each.