instance method load_schema

# File activerecord/lib/active_record/model_schema.rb, line 563
        def load_schema
          return if schema_loaded?
          @load_schema_monitor.synchronize do
            return if defined?(@columns_hash) && @columns_hash

            load_schema!

            @schema_loaded = true
          rescue
            reload_schema_from_cache # If the schema loading failed half way through, we must reset the state.
            raise
          end
        end