@@ -31,12 +31,12 @@ module ActiveRecord private def preload_one_association(records, association, preload_options={}) - reflection = reflections[association] - raise ConfigurationError, "Association named '#{ association }' was not found; perhaps you misspelled it?" unless reflection - - # Not all records have the same class, so group then preload. - records.group_by(&:class).each do |klass, records| - reflection = klass.reflections[association] + class_to_reflection = {} + # Not all records have the same class, so group then preload + # group on the reflection itself so that if various subclass share the same association then we do not split them + # unncessarily + records.group_by {|record| class_to_reflection[record.class] ||= record.class.reflections[association]}.each do |reflection, records| + raise ConfigurationError, "Association named '#{ association }' was not found; perhaps you misspelled it?" unless reflection send("preload_#{reflection.macro}_association", records, reflection, preload_options) end end activerecord/lib/active_record/association_preload.rb @@ -603,4 +603,10 @@ class EagerAssociationTest < ActiveRecord::TestCase assert_equal 3, authors(:david).posts_with_comments.count(:conditions => "length(comments.body) > 15") end end + + def test_load_with_sti_sharing_association + assert_queries(2) do #should not do 1 query per subclass + Comment.find :all, :include => :post + end + end end activerecord/test/cases/associations/eager_test.rb 0cbdd96c349c56c47299ca3c2bfa5d8c4f5e5a11 Frederick Cheung frederick.cheung@gmail.com http://github.com/rails/rails/commit/236f0bb67adecbc1e6dac5258e4a8cb310ffd7a4 236f0bb67adecbc1e6dac5258e4a8cb310ffd7a4 2008-05-11T14:14:07-07:00 2008-05-06T16:12:17-07:00 When preloading group by reflection rather than by class [#125 state:resolved] This avoids extra queries when several subclasses inherit the association from their parent class, while still coping with subclasses redefining associations. Signed-off-by: Pratik Naik <pratiknaik@gmail.com> aaca136f3ba80f589e24595cd953f064697ef0bb Pratik Naik pratiknaik@gmail.com