each_connection_pool

# File activerecord/lib/active_record/connection_adapters/abstract/connection_handler.rb, line 120
      def each_connection_pool(role = nil, &block) # :nodoc:
        role = nil if role == :all
        return enum_for(__method__, role) unless block_given?

        connection_name_to_pool_manager.each_value do |manager|
          manager.each_pool_config(role) do |pool_config|
            yield pool_config.pool
          end
        end
      end