performance optimization

2 files changed, 13 insertions, 4 deletions

diff --git a/lib/arel/relations/join.rb b/lib/arel/relations/join.rb
index 5356e57394..c1c3150629 100644
--- a/lib/arel/relations/join.rb
+++ b/lib/arel/relations/join.rb
@@ -44,10 +44,10 @@ module Arel
     end
     
     def relation_for(attribute)
-      x = [externalize(relation1), externalize(relation2)].max do |r1, r2|
+      [externalize(relation1), externalize(relation2)].max do |r1, r2|
         o1, o2 = r1.relation_for(attribute), r2.relation_for(attribute)
         a1, a2 = o1 && o1[attribute], o2 && o2[attribute]
-        
+      
         attribute / a1 <=> attribute / a2
       end.relation_for(attribute)
     end
diff --git a/lib/arel/relations/relation.rb b/lib/arel/relations/relation.rb
index cd58f0f15c..fc47a129a0 100644
--- a/lib/arel/relations/relation.rb
+++ b/lib/arel/relations/relation.rb
@@ -138,12 +138,21 @@ module Arel
       def attribute_for_name(name)
         attributes.detect { |a| a.alias_or_name.to_s == name.to_s }
       end
-
+      
+      # TESTME - added relation_for(x)[x] because of AR
       def attribute_for_attribute(attribute)
         attributes.select { |a| a =~ attribute }.max do |a1, a2|
-          (attribute / a1) <=> (attribute / a2)
+          (attribute / relation_for(a1)[a1]) <=> (attribute / relation_for(a2)[a2])
+        end
+      end
+      
+      def attribute_for_attribute_with_memoization(attribute)
+        @attribute_for_attribute ||= Hash.new do |h, a|
+          h[a] = attribute_for_attribute_without_memoization(a)
         end
+        @attribute_for_attribute[attribute]
       end
+      alias_method_chain :attribute_for_attribute, :memoization
     end
     include AttributeAccessable