reduce method calls on arel

activerecord/lib/active_record/relation/calculations.rb

@@ -166,7 +166,7 @@ def perform_calculation(operation, column_name, options = {})
       if operation == "count"
         column_name ||= (select_for_count || :all)
 
-        if arel.joins(arel) =~ /LEFT OUTER/i
+        if arel.join_sql =~ /LEFT OUTER/i
           distinct = true
           column_name = @klass.primary_key if column_name == :all
         end

activerecord/lib/active_record/relation/finder_methods.rb

@@ -196,7 +196,7 @@ def find_with_associations
 
     def construct_relation_for_association_calculations
       including = (@eager_load_values + @includes_values).uniq
-      join_dependency = ActiveRecord::Associations::ClassMethods::JoinDependency.new(@klass, including, arel.joins(arel))
+      join_dependency = ActiveRecord::Associations::ClassMethods::JoinDependency.new(@klass, including, arel.join_sql)
       relation = except(:includes, :eager_load, :preload)
       apply_join_dependency(relation, join_dependency)
     end

activerecord/lib/active_record/relation/query_methods.rb

@@ -180,7 +180,7 @@ def custom_join_sql(*joins)
         arel.join(join)
       end
 
-      arel.joins(arel)
+      arel.join_sql
     end
 
     def build_arel