1 files changed, 6 insertions, 2 deletions
diff --git a/activerecord/lib/active_record/associations/preloader/association.rb b/activerecord/lib/active_record/associations/preloader/association.rb
index 33c8619359..c0639742be 100644
--- a/activerecord/lib/active_record/associations/preloader/association.rb
+++ b/activerecord/lib/active_record/associations/preloader/association.rb
@@ -104,11 +104,11 @@ module ActiveRecord
         end
 
         def association_key_type
-          @klass.column_for_attribute(association_key_name).type
+          @klass.type_for_attribute(association_key_name.to_s).type
         end
 
         def owner_key_type
-          @model.column_for_attribute(owner_key_name).type
+          @model.type_for_attribute(owner_key_name.to_s).type
         end
 
         def load_slices(slices)
@@ -151,6 +151,10 @@ module ActiveRecord
             end
           end
 
+          if preload_values[:readonly] || values[:readonly]
+            scope.readonly!
+          end
+
           if options[:as]
             scope.where!(klass.table_name => { reflection.type => model.base_class.sti_name })
           end