Adapters can specify maximum number of ids they support in a list of expressions

(default is nil meaning unlimited but Oracle imposes a limit of 1000)
Limit is used to make multiple queries when preloading associated has_many or habtm records

1 files changed, 52 insertions, 0 deletions

diff --git a/activerecord/test/cases/associations/eager_test.rb b/activerecord/test/cases/associations/eager_test.rb
index 66fb5ac1e1..c532522e76 100644
--- a/activerecord/test/cases/associations/eager_test.rb
+++ b/activerecord/test/cases/associations/eager_test.rb
@@ -79,6 +79,58 @@ class EagerAssociationTest < ActiveRecord::TestCase
     end
   end
 
+  def test_preloading_has_many_in_multiple_queries_with_more_ids_than_database_can_handle
+    Post.connection.expects(:ids_in_list_limit).at_least_once.returns(5)
+    posts = Post.find(:all, :include=>:comments)
+    assert_equal 7, posts.size
+  end
+
+  def test_preloading_has_many_in_one_queries_when_database_has_no_limit_on_ids_it_can_handle
+    Post.connection.expects(:ids_in_list_limit).at_least_once.returns(nil)
+    posts = Post.find(:all, :include=>:comments)
+    assert_equal 7, posts.size
+  end
+
+  def test_preloading_habtm_in_multiple_queries_with_more_ids_than_database_can_handle
+    Post.connection.expects(:ids_in_list_limit).at_least_once.returns(5)
+    posts = Post.find(:all, :include=>:categories)
+    assert_equal 7, posts.size
+  end
+
+  def test_preloading_habtm_in_one_queries_when_database_has_no_limit_on_ids_it_can_handle
+    Post.connection.expects(:ids_in_list_limit).at_least_once.returns(nil)
+    posts = Post.find(:all, :include=>:categories)
+    assert_equal 7, posts.size
+  end
+  
+  def test_load_associated_records_in_one_query_when_adapter_has_no_limit
+    Post.connection.expects(:ids_in_list_limit).at_least_once.returns(nil)
+    Post.expects(:i_was_called).with([1,2,3,4,5,6,7]).returns([1])
+    associated_records = Post.send(:associated_records, [1,2,3,4,5,6,7]) do |some_ids|
+      Post.i_was_called(some_ids)
+    end
+    assert_equal [1], associated_records
+  end
+
+  def test_load_associated_records_in_several_queries_when_many_ids_passed
+    Post.connection.expects(:ids_in_list_limit).at_least_once.returns(5)
+    Post.expects(:i_was_called).with([1,2,3,4,5]).returns([1])
+    Post.expects(:i_was_called).with([6,7]).returns([6])
+    associated_records = Post.send(:associated_records, [1,2,3,4,5,6,7]) do |some_ids|
+      Post.i_was_called(some_ids)
+    end
+    assert_equal [1,6], associated_records
+  end
+
+  def test_load_associated_records_in_one_query_when_a_few_ids_passed
+    Post.connection.expects(:ids_in_list_limit).at_least_once.returns(5)
+    Post.expects(:i_was_called).with([1,2,3]).returns([1])
+    associated_records = Post.send(:associated_records, [1,2,3]) do |some_ids|
+      Post.i_was_called(some_ids)
+    end
+    assert_equal [1], associated_records
+  end
+
   def test_including_duplicate_objects_from_belongs_to
     popular_post = Post.create!(:title => 'foo', :body => "I like cars!")
     comment = popular_post.comments.create!(:body => "lol")