Rails4.2でのActiveRecordのcomplied attribute_methodを速くするpatch(だけどとても危険)

dangerous_fasten_ar_attribute_method.patch

diff --git activerecord/lib/active_record/attribute_methods/read.rb activerecord/lib/active_record/attribute_methods/read.rb
index 20f0936..77bd11d 100644
--- activerecord/lib/active_record/attribute_methods/read.rb
+++ activerecord/lib/active_record/attribute_methods/read.rb
@@ -33,6 +33,17 @@ module ActiveRecord
         end
       }.new

+      TextReaderMethodCache = Class.new(AttributeMethodCache) {
+        def method_body(method_name, const_name)
+          <<-EOMETHOD
+          def #{method_name}
+            name = ::ActiveRecord::AttributeMethods::AttrNames::ATTR_#{const_name}
+            @attributes.fetch_original_value(name)
+          end
+          EOMETHOD
+        end
+      }.new
+
       extend ActiveSupport::Concern

       module ClassMethods
@@ -51,7 +62,7 @@ module ActiveRecord

         if Module.methods_transplantable?
           def define_method_attribute(name)
-            method = ReaderMethodCache[name]
+            method = (self.columns_hash[name].text? && !(self.serialized_attributes.key? name)) ? TextReaderMethodCache[name] : ReaderMethodCache[name]
             generated_attribute_methods.module_eval { define_method name, method }
           end
         else
diff --git activerecord/lib/active_record/attribute_set.rb activerecord/lib/active_record/attribute_set.rb
index 66fcaf6..4371eab 100644
--- activerecord/lib/active_record/attribute_set.rb
+++ activerecord/lib/active_record/attribute_set.rb
@@ -31,6 +31,10 @@ module ActiveRecord
       self[name].value { |n| yield n if block_given? }
     end

+    def fetch_original_value(name)
+      attributes.values[name]
+    end
+
     def write_from_database(name, value)
       attributes[name] = self[name].with_value_from_database(value)
     end
diff --git activerecord/lib/active_record/attribute_set/builder.rb activerecord/lib/active_record/attribute_set/builder.rb
index 6f6b5ab..311e6c2 100644
--- activerecord/lib/active_record/attribute_set/builder.rb
+++ activerecord/lib/active_record/attribute_set/builder.rb
@@ -64,10 +64,14 @@ module ActiveRecord
       end
     end

-    protected

     attr_reader :types, :values, :additional_types, :delegate_hash

+    def type_of(name)
+      additional_types.fetch(name, types[name])
+    end
+
+    protected
     private

     def assign_default_value(name)