Removed the default order by id on has_and_belongs_to_many queries as it could kill performance on large sets (you can still specify by hand with :order)

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@1162 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

2 files changed, 15 insertions, 7 deletions

diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index 810fc94d97..217413999e 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Removed the default order by id on has_and_belongs_to_many queries as it could kill performance on large sets (you can still specify by hand with :order)
+
 * Fixed that Base.silence should restore the old logger level when done, not just set it to DEBUG #1084 [yon@milliped.com]
 
 * Fixed boolean saving on Oracle #1093 [mparrish@pearware.org]
diff --git a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
index eda6992243..85f4122138 100644
--- a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
@@ -7,7 +7,7 @@ module ActiveRecord
         @association_foreign_key = options[:association_foreign_key] || Inflector.underscore(Inflector.demodulize(association_class_name)) + "_id"
         @association_table_name = options[:table_name] || @association_class.table_name
         @join_table = options[:join_table]
-        @order = options[:order] || "t.#{@association_class.primary_key}"
+        @order = options[:order]
 
         construct_sql
       end
@@ -146,12 +146,18 @@ module ActiveRecord
 
         def construct_sql
           interpolate_sql_options!(@options, :finder_sql, :delete_sql)
-          @finder_sql = @options[:finder_sql] ||
-                "SELECT t.*, j.* FROM #{@join_table} j, #{@association_table_name} t " +
-                "WHERE t.#{@association_class.primary_key} = j.#{@association_foreign_key} AND " +
-                "j.#{@association_class_primary_key_name} = #{@owner.quoted_id} " +
-                (@options[:conditions] ? " AND " + interpolate_sql(@options[:conditions]) : "") + " " +
-                "ORDER BY #{@order}"
+          
+          if @options[:finder_sql]
+            @finder_sql = @options[:finder_sql]
+          else
+            @finder_sql = 
+              "SELECT t.*, j.* FROM #{@join_table} j, #{@association_table_name} t " +
+              "WHERE t.#{@association_class.primary_key} = j.#{@association_foreign_key} AND " +
+              "j.#{@association_class_primary_key_name} = #{@owner.quoted_id} "
+            
+            @finder_sql << " AND #{interpolate_sql(@options[:conditions])}" if @options[:conditions]
+            @finder_sql << "ORDER BY #{@order}" if @order
+          end
         end
     end
   end