columns are lazily typecast, so no more calls to result_as_array

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -719,7 +719,7 @@ def exec_query(sql, name = 'SQL', binds = [])
             }
           end
 
-          ret = Result.new(result.fields, result_as_array(result), types)
+          ret = Result.new(result.fields, result.values, types)
           result.clear
           return ret
         end