Merge pull request #5261 from carlosantoniodasilva/identity-map-removal

Remove IdentityMap

29 files changed, 44 insertions, 945 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 6fd86b1f32..5a289a5aac 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,5 +1,16 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Remove IdentityMap
+
+    IdentityMap has never graduated to be an "enabled-by-default" feature, due
+    to some inconsistencies with associations, as described in this commit:
+
+       https://github.com/rails/rails/commit/302c912bf6bcd0fa200d964ec2dc4a44abe328a6
+
+    Hence the removal from the codebase, until such issues are fixed.
+
+    *Carlos Antonio da Silva*
+
 *   Added the schema cache dump feature.
 
     `Schema cache dump` feature was implemetend. This feature can dump/load internal state of `SchemaCache` instance
diff --git a/activerecord/RUNNING_UNIT_TESTS b/activerecord/RUNNING_UNIT_TESTS
index a1ed6712c5..2c310e7ac3 100644
--- a/activerecord/RUNNING_UNIT_TESTS
+++ b/activerecord/RUNNING_UNIT_TESTS
@@ -26,13 +26,6 @@ You can run all the tests for a given database via rake:
 
 The 'rake test' task will run all the tests for mysql, mysql2, sqlite3 and postgresql.
 
-== Identity Map
-
-By default the tests run with the Identity Map turned off. But all tests should pass whether or
-not the identity map is on or off. You can turn it on using the IM env variable:
-
-  $ IM=true ruby -Itest test/case/base_test.rb
-
 == Config file
 
 By default, the config file is expected to be at the path test/config.yml. You can specify a
diff --git a/activerecord/lib/active_record.rb b/activerecord/lib/active_record.rb
index 73c8a06ab7..0cb0644bcf 100644
--- a/activerecord/lib/active_record.rb
+++ b/activerecord/lib/active_record.rb
@@ -65,7 +65,6 @@ module ActiveRecord
     autoload :DynamicFinderMatch
     autoload :DynamicScopeMatch
     autoload :Explain
-    autoload :IdentityMap
     autoload :Inheritance
     autoload :Integration
     autoload :Migration
diff --git a/activerecord/lib/active_record/associations/association.rb b/activerecord/lib/active_record/associations/association.rb
index 512c52338e..fb0ca15c23 100644
--- a/activerecord/lib/active_record/associations/association.rb
+++ b/activerecord/lib/active_record/associations/association.rb
@@ -45,7 +45,6 @@ module ActiveRecord
       # Resets the \loaded flag to +false+ and sets the \target to +nil+.
       def reset
         @loaded = false
-        IdentityMap.remove(target) if IdentityMap.enabled? && target
         @target = nil
       end
 
@@ -135,17 +134,7 @@ module ActiveRecord
       # ActiveRecord::RecordNotFound is rescued within the method, and it is
       # not reraised. The proxy is \reset and +nil+ is the return value.
       def load_target
-        if find_target?
-          begin
-            if IdentityMap.enabled? && association_class && association_class.respond_to?(:base_class)
-              @target = IdentityMap.get(association_class, owner[reflection.foreign_key])
-            end
-          rescue NameError
-            nil
-          ensure
-            @target ||= find_target
-          end
-        end
+        @target ||= find_target if find_target?
         loaded! unless loaded?
         target
       rescue ActiveRecord::RecordNotFound
diff --git a/activerecord/lib/active_record/attribute_methods/dirty.rb b/activerecord/lib/active_record/attribute_methods/dirty.rb
index 3a737e5b35..11c63591e3 100644
--- a/activerecord/lib/active_record/attribute_methods/dirty.rb
+++ b/activerecord/lib/active_record/attribute_methods/dirty.rb
@@ -22,8 +22,6 @@ module ActiveRecord
         if status = super
           @previously_changed = changes
           @changed_attributes.clear
-        elsif IdentityMap.enabled?
-          IdentityMap.remove(self)
         end
         status
       end
@@ -34,9 +32,6 @@ module ActiveRecord
           @previously_changed = changes
           @changed_attributes.clear
         end
-      rescue
-        IdentityMap.remove(self) if IdentityMap.enabled?
-        raise
       end
 
       # <tt>reload</tt> the record and clears changed attributes.
diff --git a/activerecord/lib/active_record/autosave_association.rb b/activerecord/lib/active_record/autosave_association.rb
index eb3ae7014e..be0af081d1 100644
--- a/activerecord/lib/active_record/autosave_association.rb
+++ b/activerecord/lib/active_record/autosave_association.rb
@@ -328,7 +328,6 @@ module ActiveRecord
         autosave = reflection.options[:autosave]
 
         if records = associated_records_to_validate_or_save(association, @new_record_before_save, autosave)
-          begin
           records.each do |record|
             next if record.destroyed?
 
@@ -348,11 +347,6 @@ module ActiveRecord
 
             raise ActiveRecord::Rollback unless saved
           end
-          rescue
-            records.each {|x| IdentityMap.remove(x) } if IdentityMap.enabled?
-            raise
-          end
-
         end
 
         # reconstruct the scope now that we know the owner's id
diff --git a/activerecord/lib/active_record/counter_cache.rb b/activerecord/lib/active_record/counter_cache.rb
index 8d5388e1f3..f52979ebd9 100644
--- a/activerecord/lib/active_record/counter_cache.rb
+++ b/activerecord/lib/active_record/counter_cache.rb
@@ -69,8 +69,6 @@ module ActiveRecord
         "#{quoted_column} = COALESCE(#{quoted_column}, 0) #{operator} #{value.abs}"
       end
 
-      IdentityMap.remove_by_id(symbolized_base_class, id) if IdentityMap.enabled?
-
       update_all(updates.join(', '), primary_key => id)
     end
 
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index b82d5b5621..5c42e8f719 100644
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -796,9 +796,7 @@ module ActiveRecord
                 @fixture_cache[fixture_name].delete(fixture) if force_reload
 
                 if @loaded_fixtures[fixture_name][fixture.to_s]
-                  ActiveRecord::IdentityMap.without do
-                    @fixture_cache[fixture_name][fixture] ||= @loaded_fixtures[fixture_name][fixture.to_s].find
-                  end
+                  @fixture_cache[fixture_name][fixture] ||= @loaded_fixtures[fixture_name][fixture.to_s].find
                 else
                   raise StandardError, "No entry named '#{fixture}' found for fixture collection '#{fixture_name}'"
                 end
diff --git a/activerecord/lib/active_record/identity_map.rb b/activerecord/lib/active_record/identity_map.rb
deleted file mode 100644
index d9777bb2f6..0000000000
--- a/activerecord/lib/active_record/identity_map.rb
+++ /dev/null
@@ -1,144 +0,0 @@
-module ActiveRecord
-  # = Active Record Identity Map
-  #
-  # Ensures that each object gets loaded only once by keeping every loaded
-  # object in a map. Looks up objects using the map when referring to them.
-  #
-  # More information on Identity Map pattern:
-  #   http://www.martinfowler.com/eaaCatalog/identityMap.html
-  #
-  # == Configuration
-  #
-  # In order to enable IdentityMap, set <tt>config.active_record.identity_map = true</tt>
-  # in your <tt>config/application.rb</tt> file.
-  #
-  # IdentityMap is disabled by default and still in development (i.e. use it with care).
-  #
-  # == Associations
-  #
-  # Active Record Identity Map does not track associations yet. For example:
-  #
-  #   comment = @post.comments.first
-  #   comment.post = nil
-  #   @post.comments.include?(comment) #=> true
-  #
-  # Ideally, the example above would return false, removing the comment object from the
-  # post association when the association is nullified. This may cause side effects, as
-  # in the situation below, if Identity Map is enabled:
-  #
-  #   Post.has_many :comments, :dependent => :destroy
-  #
-  #   comment = @post.comments.first
-  #   comment.post = nil
-  #   comment.save
-  #   Post.destroy(@post.id)
-  #
-  # Without using Identity Map, the code above will destroy the @post object leaving
-  # the comment object intact. However, once we enable Identity Map, the post loaded
-  # by Post.destroy is exactly the same object as the object @post. As the object @post
-  # still has the comment object in @post.comments, once Identity Map is enabled, the
-  # comment object will be accidently removed.
-  #
-  # This inconsistency is meant to be fixed in future Rails releases.
-  #
-  module IdentityMap
-
-    class << self
-      def enabled=(flag)
-        Thread.current[:identity_map_enabled] = flag
-      end
-
-      def enabled
-        Thread.current[:identity_map_enabled]
-      end
-      alias enabled? enabled
-
-      def repository
-        Thread.current[:identity_map] ||= Hash.new { |h,k| h[k] = {} }
-      end
-
-      def use
-        old, self.enabled = enabled, true
-
-        yield if block_given?
-      ensure
-        self.enabled = old
-        clear
-      end
-
-      def without
-        old, self.enabled = enabled, false
-
-        yield if block_given?
-      ensure
-        self.enabled = old
-      end
-
-      def get(klass, primary_key)
-        record = repository[klass.symbolized_sti_name][primary_key]
-
-        if record.is_a?(klass)
-          ActiveSupport::Notifications.instrument("identity.active_record",
-            :line => "From Identity Map (id: #{primary_key})",
-            :name => "#{klass} Loaded",
-            :connection_id => object_id)
-
-          record
-        else
-          nil
-        end
-      end
-
-      def add(record)
-        repository[record.class.symbolized_sti_name][record.id] = record
-      end
-
-      def remove(record)
-        repository[record.class.symbolized_sti_name].delete(record.id)
-      end
-
-      def remove_by_id(symbolized_sti_name, id)
-        repository[symbolized_sti_name].delete(id)
-      end
-
-      def clear
-        repository.clear
-      end
-    end
-
-    # Reinitialize an Identity Map model object from +coder+.
-    # +coder+ must contain the attributes necessary for initializing an empty
-    # model object.
-    def reinit_with(coder)
-      @attributes_cache = {}
-      dirty      = @changed_attributes.keys
-      attributes = self.class.initialize_attributes(coder['attributes'].except(*dirty))
-      @attributes.update(attributes)
-      @changed_attributes.update(coder['attributes'].slice(*dirty))
-      @changed_attributes.delete_if{|k,v| v.eql? @attributes[k]}
-
-      run_callbacks :find
-
-      self
-    end
-
-    class Middleware
-      def initialize(app)
-        @app = app
-      end
-
-      def call(env)
-        enabled = IdentityMap.enabled
-        IdentityMap.enabled = true
-
-        response = @app.call(env)
-        response[2] = Rack::BodyProxy.new(response[2]) do
-          IdentityMap.enabled = enabled
-          IdentityMap.clear
-        end
-
-        response
-      end
-    end
-  end
-end
diff --git a/activerecord/lib/active_record/inheritance.rb b/activerecord/lib/active_record/inheritance.rb
index 2c766411a0..ebe244c6a6 100644
--- a/activerecord/lib/active_record/inheritance.rb
+++ b/activerecord/lib/active_record/inheritance.rb
@@ -63,26 +63,9 @@ module ActiveRecord
       # single-table inheritance model that makes it possible to create
       # objects of different types from the same table.
       def instantiate(record, column_types = {})
-        sti_class = find_sti_class(record[inheritance_column])
-        record_id = sti_class.primary_key && record[sti_class.primary_key]
-
-        if ActiveRecord::IdentityMap.enabled? && record_id
-          if (column = sti_class.columns_hash[sti_class.primary_key]) && column.number?
-            record_id = record_id.to_i
-          end
-          if instance = IdentityMap.get(sti_class, record_id)
-            instance.reinit_with('attributes' => record)
-          else
-            instance = sti_class.allocate.init_with('attributes' => record)
-            IdentityMap.add(instance)
-          end
-        else
-          column_types = sti_class.decorate_columns(column_types)
-          instance = sti_class.allocate.init_with('attributes' => record,
-                                                  'column_types' => column_types)
-        end
-
-        instance
+        sti_class    = find_sti_class(record[inheritance_column])
+        column_types = sti_class.decorate_columns(column_types)
+        sti_class.allocate.init_with('attributes' => record, 'column_types' => column_types)
       end
 
       # For internal use.
diff --git a/activerecord/lib/active_record/model.rb b/activerecord/lib/active_record/model.rb
index 86de5ab2fa..105d1e0e2b 100644
--- a/activerecord/lib/active_record/model.rb
+++ b/activerecord/lib/active_record/model.rb
@@ -60,7 +60,6 @@ module ActiveRecord
     include AttributeMethods
     include Callbacks, ActiveModel::Observing, Timestamp
     include Associations
-    include IdentityMap
     include ActiveModel::SecurePassword
     include AutosaveAssociation, NestedAttributes
     include Aggregations, Transactions, Reflection, Serialization, Store
diff --git a/activerecord/lib/active_record/persistence.rb b/activerecord/lib/active_record/persistence.rb
index 09502bb52c..35c922e979 100644
--- a/activerecord/lib/active_record/persistence.rb
+++ b/activerecord/lib/active_record/persistence.rb
@@ -115,10 +115,7 @@ module ActiveRecord
     # callbacks, Observer methods, or any <tt>:dependent</tt> association
     # options, use <tt>#destroy</tt>.
     def delete
-      if persisted?
-        self.class.delete(id)
-        IdentityMap.remove(self) if IdentityMap.enabled?
-      end
+      self.class.delete(id) if persisted?
       @destroyed = true
       freeze
     end
@@ -129,7 +126,6 @@ module ActiveRecord
       destroy_associations
 
       if persisted?
-        IdentityMap.remove(self) if IdentityMap.enabled?
         pk         = self.class.primary_key
         column     = self.class.columns_hash[pk]
         substitute = connection.substitute_at(column, 0)
@@ -284,11 +280,9 @@ module ActiveRecord
       clear_aggregation_cache
       clear_association_cache
 
-      IdentityMap.without do
-        fresh_object = self.class.unscoped { self.class.find(id, options) }
-        @attributes.update(fresh_object.instance_variable_get('@attributes'))
-        @columns_hash = fresh_object.instance_variable_get('@columns_hash')
-      end
+      fresh_object = self.class.unscoped { self.class.find(id, options) }
+      @attributes.update(fresh_object.instance_variable_get('@attributes'))
+      @columns_hash = fresh_object.instance_variable_get('@columns_hash')
 
       @attributes_cache = {}
       self
@@ -363,10 +357,8 @@ module ActiveRecord
       attributes_values = arel_attributes_with_values_for_create(!id.nil?)
 
       new_id = self.class.unscoped.insert attributes_values
-
       self.id ||= new_id if self.class.primary_key
 
-      IdentityMap.add(self) if IdentityMap.enabled?
       @new_record = false
       id
     end
diff --git a/activerecord/lib/active_record/railtie.rb b/activerecord/lib/active_record/railtie.rb
index 516c450f85..ee3a6bf8c0 100644
--- a/activerecord/lib/active_record/railtie.rb
+++ b/activerecord/lib/active_record/railtie.rb
@@ -53,11 +53,6 @@ module ActiveRecord
       ActiveSupport.on_load(:active_record) { self.logger ||= ::Rails.logger }
     end
 
-    initializer "active_record.identity_map" do |app|
-      config.app_middleware.insert_after "::ActionDispatch::Callbacks",
-        "ActiveRecord::IdentityMap::Middleware" if config.active_record.delete(:identity_map)
-    end
-
     initializer "active_record.set_configs" do |app|
       ActiveSupport.on_load(:active_record) do
         if app.config.active_record.delete(:whitelist_attributes)
diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb
index 7531e1fe6f..6f39708ec3 100644
--- a/activerecord/lib/active_record/relation.rb
+++ b/activerecord/lib/active_record/relation.rb
@@ -168,13 +168,7 @@ module ActiveRecord
       default_scoped = with_default_scope
 
       if default_scoped.equal?(self)
-        @records = if @readonly_value.nil? && !@klass.locking_enabled?
-          eager_loading? ? find_with_associations : @klass.find_by_sql(arel, @bind_values)
-        else
-          IdentityMap.without do
-            eager_loading? ? find_with_associations : @klass.find_by_sql(arel, @bind_values)
-          end
-        end
+        @records = eager_loading? ? find_with_associations : @klass.find_by_sql(arel, @bind_values)
 
         preload = @preload_values
         preload +=  @includes_values unless eager_loading?
@@ -274,7 +268,6 @@ module ActiveRecord
     #   # The same idea applies to limit and order
     #   Book.where('title LIKE ?', '%Rails%').order(:created_at).limit(5).update_all(:author => 'David')
     def update_all(updates, conditions = nil, options = {})
-      IdentityMap.repository[symbolized_base_class].clear if IdentityMap.enabled?
       if conditions || options.present?
         where(conditions).apply_finder_options(options.slice(:limit, :order)).update_all(updates)
       else
@@ -404,7 +397,6 @@ module ActiveRecord
     # If you need to destroy dependent associations or call your <tt>before_*</tt> or
     # +after_destroy+ callbacks, use the +destroy_all+ method instead.
     def delete_all(conditions = nil)
-      IdentityMap.repository[symbolized_base_class] = {} if IdentityMap.enabled?
       if conditions
         where(conditions).delete_all
       else
@@ -437,7 +429,6 @@ module ActiveRecord
     #   # Delete multiple rows
     #   Todo.delete([2,3,4])
     def delete(id_or_array)
-      IdentityMap.remove_by_id(self.symbolized_base_class, id_or_array) if IdentityMap.enabled?
       where(primary_key => id_or_array).delete_all
     end
 
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
index adfacf37ee..52e67ecc6e 100644
--- a/activerecord/lib/active_record/relation/finder_methods.rb
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -318,17 +318,7 @@ module ActiveRecord
     def find_one(id)
       id = id.id if ActiveRecord::Base === id
 
-      if IdentityMap.enabled? && where_values.blank? &&
-        limit_value.blank? && order_values.blank? &&
-        includes_values.blank? && preload_values.blank? &&
-        readonly_value.nil? && joins_values.blank? &&
-        !@klass.locking_enabled? &&
-        record = IdentityMap.get(@klass, id)
-        return record
-      end
-
       column = columns_hash[primary_key]
-
       substitute = connection.substitute_at(column, @bind_values.length)
       relation = where(table[primary_key].eq(substitute))
       relation.bind_values += [[column, id]]
diff --git a/activerecord/lib/active_record/test_case.rb b/activerecord/lib/active_record/test_case.rb
index 4d881f0f7d..fcaa4b74a6 100644
--- a/activerecord/lib/active_record/test_case.rb
+++ b/activerecord/lib/active_record/test_case.rb
@@ -7,20 +7,10 @@ module ActiveRecord
   #
   # Defines some test assertions to test against SQL queries.
   class TestCase < ActiveSupport::TestCase #:nodoc:
-    setup :cleanup_identity_map
-
-    def setup
-      cleanup_identity_map
-    end
-
     def teardown
       SQLCounter.log.clear
     end
 
-    def cleanup_identity_map
-      ActiveRecord::IdentityMap.clear
-    end
-
     def assert_date_from_db(expected, actual, message = nil)
       # SybaseAdapter doesn't have a separate column type just for dates,
       # so the time is in the string and incorrectly formatted
diff --git a/activerecord/lib/active_record/transactions.rb b/activerecord/lib/active_record/transactions.rb
index b492377d18..743dfc5a38 100644
--- a/activerecord/lib/active_record/transactions.rb
+++ b/activerecord/lib/active_record/transactions.rb
@@ -251,7 +251,6 @@ module ActiveRecord
       remember_transaction_record_state
       yield
     rescue Exception
-      IdentityMap.remove(self) if IdentityMap.enabled?
       restore_transaction_record_state
       raise
     ensure
@@ -270,7 +269,6 @@ module ActiveRecord
     def rolledback!(force_restore_state = false) #:nodoc:
       run_callbacks :rollback
     ensure
-      IdentityMap.remove(self) if IdentityMap.enabled?
       restore_transaction_record_state(force_restore_state)
     end
 
diff --git a/activerecord/test/cases/associations/eager_load_includes_full_sti_class_test.rb b/activerecord/test/cases/associations/eager_load_includes_full_sti_class_test.rb
index 7965bb404c..3044a8c312 100644
--- a/activerecord/test/cases/associations/eager_load_includes_full_sti_class_test.rb
+++ b/activerecord/test/cases/associations/eager_load_includes_full_sti_class_test.rb
@@ -27,7 +27,6 @@ class EagerLoadIncludeFullStiClassNamesTest < ActiveRecord::TestCase
     post = Namespaced::Post.find_by_title( 'Great stuff', :include => :tagging )
     assert_nil post.tagging
 
-    ActiveRecord::IdentityMap.clear
     ActiveRecord::Base.store_full_sti_class = true
     post = Namespaced::Post.find_by_title( 'Great stuff', :include => :tagging )
     assert_instance_of Tagging, post.tagging
diff --git a/activerecord/test/cases/associations/eager_test.rb b/activerecord/test/cases/associations/eager_test.rb
index b79c69bbb5..b27a93f857 100644
--- a/activerecord/test/cases/associations/eager_test.rb
+++ b/activerecord/test/cases/associations/eager_test.rb
@@ -197,7 +197,7 @@ class EagerAssociationTest < ActiveRecord::TestCase
     author = authors(:david)
     post = author.post_about_thinking_with_last_comment
     last_comment = post.last_comment
-    author = assert_queries(ActiveRecord::IdentityMap.enabled? ? 2 : 3) { Author.find(author.id, :include => {:post_about_thinking_with_last_comment => :last_comment})} # find the author, then find the posts, then find the comments
+    author = assert_queries(3) { Author.find(author.id, :include => {:post_about_thinking_with_last_comment => :last_comment})} # find the author, then find the posts, then find the comments
     assert_no_queries do
       assert_equal post, author.post_about_thinking_with_last_comment
       assert_equal last_comment, author.post_about_thinking_with_last_comment.last_comment
@@ -208,7 +208,7 @@ class EagerAssociationTest < ActiveRecord::TestCase
     post = posts(:welcome)
     author = post.author
     author_address = author.author_address
-    post = assert_queries(ActiveRecord::IdentityMap.enabled? ? 2 : 3) { Post.find(post.id, :include => {:author_with_address => :author_address}) } # find the post, then find the author, then find the address
+    post = assert_queries(3) { Post.find(post.id, :include => {:author_with_address => :author_address}) } # find the post, then find the author, then find the address
     assert_no_queries do
       assert_equal author, post.author_with_address
       assert_equal author_address, post.author_with_address.author_address
@@ -611,9 +611,9 @@ class EagerAssociationTest < ActiveRecord::TestCase
     assert posts[1].categories.include?(categories(:general))
   end
 
-  # This is only really relevant when the identity map is off. Since the preloader for habtm
-  # gets raw row hashes from the database and then instantiates them, this test ensures that
-  # it only instantiates one actual object per record from the database.
+  # Since the preloader for habtm gets raw row hashes from the database and then
+  # instantiates them, this test ensures that it only instantiates one actual
+  # object per record from the database.
   def test_has_and_belongs_to_many_should_not_instantiate_same_records_multiple_times
     welcome    = posts(:welcome)
     categories = Category.includes(:posts)
@@ -1002,18 +1002,18 @@ class EagerAssociationTest < ActiveRecord::TestCase
     assert_equal [posts(:welcome)], posts
     assert_equal authors(:david), assert_no_queries { posts[0].author}
 
-    posts = assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 2) do
+    posts = assert_queries(2) do
       Post.find(:all, :select => 'distinct posts.*', :include => :author, :joins => [:comments], :conditions => "comments.body like 'Thank you%'", :order => 'posts.id')
     end
     assert_equal [posts(:welcome)], posts
     assert_equal authors(:david), assert_no_queries { posts[0].author}
 
-    posts = assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 2) do
+    posts = assert_queries(2) do
       Post.find(:all, :include => :author, :joins => {:taggings => :tag}, :conditions => "tags.name = 'General'", :order => 'posts.id')
     end
     assert_equal posts(:welcome, :thinking), posts
 
-    posts = assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 2) do
+    posts = assert_queries(2) do
       Post.find(:all, :include => :author, :joins => {:taggings => {:tag => :taggings}}, :conditions => "taggings_tags.super_tag_id=2", :order => 'posts.id')
     end
     assert_equal posts(:welcome, :thinking), posts
@@ -1027,7 +1027,7 @@ class EagerAssociationTest < ActiveRecord::TestCase
     assert_equal [posts(:welcome)], posts
     assert_equal authors(:david), assert_no_queries { posts[0].author}
 
-    posts = assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 2) do
+    posts = assert_queries(2) do
       Post.find(:all, :select => 'distinct posts.*', :include => :author, :joins => ["INNER JOIN comments on comments.post_id = posts.id"], :conditions => "comments.body like 'Thank you%'", :order => 'posts.id')
     end
     assert_equal [posts(:welcome)], posts
@@ -1116,7 +1116,7 @@ class EagerAssociationTest < ActiveRecord::TestCase
   def test_preloading_empty_belongs_to_polymorphic
     t = Tagging.create!(:taggable_type => 'Post', :taggable_id => Post.maximum(:id) + 1, :tag => tags(:general))
 
-    tagging = assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 2) { Tagging.preload(:taggable).find(t.id) }
+    tagging = assert_queries(2) { Tagging.preload(:taggable).find(t.id) }
     assert_no_queries { assert_nil tagging.taggable }
   end
 
diff --git a/activerecord/test/cases/associations/identity_map_test.rb b/activerecord/test/cases/associations/identity_map_test.rb
deleted file mode 100644
index 9b8635774c..0000000000
--- a/activerecord/test/cases/associations/identity_map_test.rb
+++ /dev/null
@@ -1,137 +0,0 @@
-require "cases/helper"
-require 'models/author'
-require 'models/post'
-
-if ActiveRecord::IdentityMap.enabled?
-class InverseHasManyIdentityMapTest < ActiveRecord::TestCase
-  fixtures :authors, :posts
-
-  def test_parent_instance_should_be_shared_with_every_child_on_find
-    m = Author.first
-    is = m.posts
-    is.each do |i|
-      assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
-      m.name = 'Bongo'
-      assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
-      i.author.name = 'Mungo'
-      assert_equal m.name, i.author.name, "Name of man should be the same after changes to child-owned instance"
-    end
-  end
-
-  def test_parent_instance_should_be_shared_with_eager_loaded_children
-    m = Author.find(:first, :include => :posts)
-    is = m.posts
-    is.each do |i|
-      assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
-      m.name = 'Bongo'
-      assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
-      i.author.name = 'Mungo'
-      assert_equal m.name, i.author.name, "Name of man should be the same after changes to child-owned instance"
-    end
-
-    m = Author.find(:first, :include => :posts, :order => 'posts.id')
-    is = m.posts
-    is.each do |i|
-      assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
-      m.name = 'Bongo'
-      assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
-      i.author.name = 'Mungo'
-      assert_equal m.name, i.author.name, "Name of man should be the same after changes to child-owned instance"
-    end
-  end
-
-  def test_parent_instance_should_be_shared_with_newly_built_child
-    m = Author.first
-    i = m.posts.build(:title => 'Industrial Revolution Re-enactment', :body => 'Lorem ipsum')
-    assert_not_nil i.author
-    assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
-    m.name = 'Bongo'
-    assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
-    i.author.name = 'Mungo'
-    assert_equal m.name, i.author.name, "Name of man should be the same after changes to just-built-child-owned instance"
-  end
-
-  def test_parent_instance_should_be_shared_with_newly_block_style_built_child
-    m = Author.first
-    i = m.posts.build {|ii| ii.title = 'Industrial Revolution Re-enactment'; ii.body = 'Lorem ipsum'}
-    assert_not_nil i.title, "Child attributes supplied to build via blocks should be populated"
-    assert_not_nil i.author
-    assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
-    m.name = 'Bongo'
-    assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
-    i.author.name = 'Mungo'
-    assert_equal m.name, i.author.name, "Name of man should be the same after changes to just-built-child-owned instance"
-  end
-
-  def test_parent_instance_should_be_shared_with_newly_created_child
-    m = Author.first
-    i = m.posts.create(:title => 'Industrial Revolution Re-enactment', :body => 'Lorem ipsum')
-    assert_not_nil i.author
-    assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
-    m.name = 'Bongo'
-    assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
-    i.author.name = 'Mungo'
-    assert_equal m.name, i.author.name, "Name of man should be the same after changes to newly-created-child-owned instance"
-  end
-
-  def test_parent_instance_should_be_shared_with_newly_created_via_bang_method_child
-    m = Author.first
-    i = m.posts.create!(:title => 'Industrial Revolution Re-enactment', :body => 'Lorem ipsum')
-    assert_not_nil i.author
-    assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
-    m.name = 'Bongo'
-    assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
-    i.author.name = 'Mungo'
-    assert_equal m.name, i.author.name, "Name of man should be the same after changes to newly-created-child-owned instance"
-  end
-
-  def test_parent_instance_should_be_shared_with_newly_block_style_created_child
-    m = Author.first
-    i = m.posts.create {|ii| ii.title = 'Industrial Revolution Re-enactment'; ii.body = 'Lorem ipsum'}
-    assert_not_nil i.title, "Child attributes supplied to create via blocks should be populated"
-    assert_not_nil i.author
-    assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
-    m.name = 'Bongo'
-    assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
-    i.author.name = 'Mungo'
-    assert_equal m.name, i.author.name, "Name of man should be the same after changes to newly-created-child-owned instance"
-  end
-
-  def test_parent_instance_should_be_shared_with_poked_in_child
-    m = Author.first
-    i = Post.create(:title => 'Industrial Revolution Re-enactment', :body => 'Lorem ipsum')
-    m.posts << i
-    assert_not_nil i.author
-    assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
-    m.name = 'Bongo'
-    assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
-    i.author.name = 'Mungo'
-    assert_equal m.name, i.author.name, "Name of man should be the same after changes to newly-created-child-owned instance"
-  end
-
-  def test_parent_instance_should_be_shared_with_replaced_via_accessor_children
-    m = Author.first
-    i = Post.new(:title => 'Industrial Revolution Re-enactment', :body => 'Lorem ipsum')
-    m.posts = [i]
-    assert_same m, i.author
-    assert_not_nil i.author
-    assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
-    m.name = 'Bongo'
-    assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
-    i.author.name = 'Mungo'
-    assert_equal m.name, i.author.name, "Name of man should be the same after changes to replaced-child-owned instance"
-  end
-
-  def test_parent_instance_should_be_shared_with_replaced_via_method_children
-    m = Author.first
-    i = Post.new(:title => 'Industrial Revolution Re-enactment', :body => 'Lorem ipsum')
-    m.posts = [i]
-    assert_not_nil i.author
-    assert_equal m.name, i.author.name, "Name of man should be the same before changes to parent instance"
-    m.name = 'Bongo'
-    assert_equal m.name, i.author.name, "Name of man should be the same after changes to parent instance"
-    i.author.name = 'Mungo'
-    assert_equal m.name, i.author.name, "Name of man should be the same after changes to replaced-child-owned instance"
-  end
-end
-end
diff --git a/activerecord/test/cases/autosave_association_test.rb b/activerecord/test/cases/autosave_association_test.rb
index 1376810adf..67b65c51d5 100644
--- a/activerecord/test/cases/autosave_association_test.rb
+++ b/activerecord/test/cases/autosave_association_test.rb
@@ -978,10 +978,7 @@ class TestAutosaveAssociationOnAHasOneAssociation < ActiveRecord::TestCase
     values = [@pirate.reload.catchphrase, @pirate.ship.name, *@pirate.ship.parts.map(&:name)]
     # Oracle saves empty string as NULL
     if current_adapter?(:OracleAdapter)
-      expected = ActiveRecord::IdentityMap.enabled? ?
-        [nil, nil, '', ''] :
-        [nil, nil, nil, nil]
-      assert_equal expected, values
+      assert_equal [nil, nil, nil, nil], values
     else
       assert_equal ['', '', '', ''], values
     end
@@ -1077,8 +1074,7 @@ class TestAutosaveAssociationOnABelongsToAssociation < ActiveRecord::TestCase
     @ship.save(:validate => false)
     # Oracle saves empty string as NULL
     if current_adapter?(:OracleAdapter)
-      expected = ActiveRecord::IdentityMap.enabled? ?  [nil, ''] : [nil, nil]
-      assert_equal expected, [@ship.reload.name, @ship.pirate.catchphrase]
+      assert_equal [nil, nil], [@ship.reload.name, @ship.pirate.catchphrase]
     else
       assert_equal ['', ''], [@ship.reload.name, @ship.pirate.catchphrase]
     end
diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
index 01f647b261..76b999efac 100644
--- a/activerecord/test/cases/base_test.rb
+++ b/activerecord/test/cases/base_test.rb
@@ -1139,7 +1139,7 @@ class BasicsTest < ActiveRecord::TestCase
       assert g.save
 
       # Reload and check that we have all the geometric attributes.
-      h = ActiveRecord::IdentityMap.without { Geometric.find(g.id) }
+      h = Geometric.find(g.id)
 
       assert_equal '(5,6.1)', h.a_point
       assert_equal '[(2,3),(5.5,7)]', h.a_line_segment
@@ -1168,7 +1168,7 @@ class BasicsTest < ActiveRecord::TestCase
       assert g.save
 
       # Reload and check that we have all the geometric attributes.
-      h = ActiveRecord::IdentityMap.without { Geometric.find(g.id) }
+      h = Geometric.find(g.id)
 
       assert_equal '(5,6.1)', h.a_point
       assert_equal '[(2,3),(5.5,7)]', h.a_line_segment
diff --git a/activerecord/test/cases/helper.rb b/activerecord/test/cases/helper.rb
index 9f5f012073..5c3560a33b 100644
--- a/activerecord/test/cases/helper.rb
+++ b/activerecord/test/cases/helper.rb
@@ -19,9 +19,6 @@ require 'support/connection'
 # Show backtraces for deprecated behavior for quicker cleanup.
 ActiveSupport::Deprecation.debug = true
 
-# Enable Identity Map only when ENV['IM'] is set to "true"
-ActiveRecord::IdentityMap.enabled = (ENV['IM'] == "true")
-
 # Avoid deprecation warning setting dependent_restrict_raises to false. The default is true
 ActiveRecord::Base.dependent_restrict_raises = false
 
diff --git a/activerecord/test/cases/identity_map/middleware_test.rb b/activerecord/test/cases/identity_map/middleware_test.rb
deleted file mode 100644
index 5b32a1c6d2..0000000000
--- a/activerecord/test/cases/identity_map/middleware_test.rb
+++ /dev/null
@@ -1,74 +0,0 @@
-require "cases/helper"
-require "rack"
-
-module ActiveRecord
-  module IdentityMap
-    class MiddlewareTest < ActiveRecord::TestCase
-      def setup
-        super
-        @enabled = IdentityMap.enabled
-        IdentityMap.enabled = false
-      end
-
-      def teardown
-        super
-        IdentityMap.enabled = @enabled
-        IdentityMap.clear
-      end
-
-      def test_delegates
-        called = false
-        mw = Middleware.new lambda { |env|
-          called = true
-          [200, {}, nil]
-        }
-        mw.call({})
-        assert called, 'middleware delegated'
-      end
-
-      def test_im_enabled_during_delegation
-        mw = Middleware.new lambda { |env|
-          assert IdentityMap.enabled?, 'identity map should be enabled'
-          [200, {}, nil]
-        }
-        mw.call({})
-      end
-
-      class Enum < Struct.new(:iter)
-        def each(&b)
-          iter.call(&b)
-        end
-      end
-
-      def test_im_enabled_during_body_each
-        mw = Middleware.new lambda { |env|
-          [200, {}, Enum.new(lambda { |&b|
-            assert IdentityMap.enabled?, 'identity map should be enabled'
-            b.call "hello"
-          })]
-        }
-        body = mw.call({}).last
-        body.each { |x| assert_equal 'hello', x }
-      end
-
-      def test_im_disabled_after_body_close
-        mw = Middleware.new lambda { |env| [200, {}, []] }
-        body = mw.call({}).last
-        assert IdentityMap.enabled?, 'identity map should be enabled'
-        body.close
-        assert !IdentityMap.enabled?, 'identity map should be disabled'
-      end
-
-      def test_im_cleared_after_body_close
-        mw = Middleware.new lambda { |env| [200, {}, []] }
-        body = mw.call({}).last
-
-        IdentityMap.repository['hello'] = 'world'
-        assert !IdentityMap.repository.empty?, 'repo should not be empty'
-
-        body.close
-        assert IdentityMap.repository.empty?, 'repo should be empty'
-      end
-    end
-  end
-end
diff --git a/activerecord/test/cases/identity_map_test.rb b/activerecord/test/cases/identity_map_test.rb
deleted file mode 100644
index 3efc8bf559..0000000000
--- a/activerecord/test/cases/identity_map_test.rb
+++ /dev/null
@@ -1,439 +0,0 @@
-require "cases/helper"
-
-require 'models/developer'
-require 'models/project'
-require 'models/company'
-require 'models/topic'
-require 'models/reply'
-require 'models/computer'
-require 'models/customer'
-require 'models/order'
-require 'models/post'
-require 'models/author'
-require 'models/tag'
-require 'models/tagging'
-require 'models/comment'
-require 'models/sponsor'
-require 'models/member'
-require 'models/essay'
-require 'models/subscriber'
-require "models/pirate"
-require "models/bird"
-require "models/parrot"
-
-if ActiveRecord::IdentityMap.enabled?
-class IdentityMapTest < ActiveRecord::TestCase
-  fixtures :accounts, :companies, :developers, :projects, :topics,
-    :developers_projects, :computers, :authors, :author_addresses,
-    :posts, :tags, :taggings, :comments, :subscribers
-
-  ##############################################################################
-  # Basic tests checking if IM is functioning properly on basic find operations#
-  ##############################################################################
-
-  def test_find_id
-    assert_same(Client.find(3), Client.find(3))
-  end
-
-  def test_find_id_without_identity_map
-    ActiveRecord::IdentityMap.without do
-      assert_not_same(Client.find(3), Client.find(3))
-    end
-  end
-
-  def test_find_id_use_identity_map
-    ActiveRecord::IdentityMap.enabled = false
-    ActiveRecord::IdentityMap.use do
-      assert_same(Client.find(3), Client.find(3))
-    end
-    ActiveRecord::IdentityMap.enabled = true
-  end
-
-  def test_find_pkey
-    assert_same(
-      Subscriber.find('swistak'),
-      Subscriber.find('swistak')
-    )
-  end
-
-  def test_find_by_id
-    assert_same(
-      Client.find_by_id(3),
-      Client.find_by_id(3)
-    )
-  end
-
-  def test_find_by_string_and_numeric_id
-    assert_same(
-      Client.find_by_id("3"),
-      Client.find_by_id(3)
-    )
-  end
-
-  def test_find_by_pkey
-    assert_same(
-      Subscriber.find_by_nick('swistak'),
-      Subscriber.find_by_nick('swistak')
-    )
-  end
-
-  def test_find_first_id
-    assert_same(
-      Client.find(:first, :conditions => {:id => 1}),
-      Client.find(:first, :conditions => {:id => 1})
-    )
-  end
-
-  def test_find_first_pkey
-    assert_same(
-      Subscriber.find(:first, :conditions => {:nick => 'swistak'}),
-      Subscriber.find(:first, :conditions => {:nick => 'swistak'})
-    )
-  end
-
-  def test_queries_are_not_executed_when_finding_by_id
-    Post.find 1
-    assert_no_queries do
-      Post.find 1
-    end
-  end
-
-  ##############################################################################
-  # Tests checking if IM is functioning properly on more advanced finds        #
-  # and associations                                                           #
-  ##############################################################################
-
-  def test_owner_object_is_associated_from_identity_map
-    post = Post.find(1)
-    comment = post.comments.first
-
-    assert_no_queries do
-      comment.post
-    end
-    assert_same post, comment.post
-  end
-
-  def test_associated_object_are_assigned_from_identity_map
-    post = Post.find(1)
-
-    post.comments.each do |comment|
-      assert_same post, comment.post
-      assert_equal post.object_id, comment.post.object_id
-    end
-  end
-
-  def test_creation
-    t1 = Topic.create("title" => "t1")
-    t2 = Topic.find(t1.id)
-    assert_same(t1, t2)
-  end
-
-  ##############################################################################
-  # Tests checking if IM is functioning properly on classes with multiple      #
-  # types of inheritance                                                       #
-  ##############################################################################
-
-  def test_inherited_without_type_attribute_without_identity_map
-    ActiveRecord::IdentityMap.without do
-      p1 = DestructivePirate.create!(:catchphrase => "I'm not a regular Pirate")
-      p2 = Pirate.find(p1.id)
-      assert_not_same(p1, p2)
-    end
-  end
-
-  def test_inherited_with_type_attribute_without_identity_map
-    ActiveRecord::IdentityMap.without do
-      c = comments(:sub_special_comment)
-      c1 = SubSpecialComment.find(c.id)
-      c2 = Comment.find(c.id)
-      assert_same(c1.class, c2.class)
-    end
-  end
-
-  def test_inherited_without_type_attribute
-    p1 = DestructivePirate.create!(:catchphrase => "I'm not a regular Pirate")
-    p2 = Pirate.find(p1.id)
-    assert_not_same(p1, p2)
-  end
-
-  def test_inherited_with_type_attribute
-    c = comments(:sub_special_comment)
-    c1 = SubSpecialComment.find(c.id)
-    c2 = Comment.find(c.id)
-    assert_same(c1, c2)
-  end
-
-  ##############################################################################
-  # Tests checking dirty attribute behavior with IM                            #
-  ##############################################################################
-
-  def test_loading_new_instance_should_not_update_dirty_attributes
-    swistak = Subscriber.find(:first, :conditions => {:nick => 'swistak'})
-    swistak.name = "Swistak Sreberkowiec"
-    assert_equal(["name"], swistak.changed)
-    assert_equal({"name" => ["Marcin Raczkowski", "Swistak Sreberkowiec"]}, swistak.changes)
-
-    assert swistak.name_changed?
-    assert_equal("Swistak Sreberkowiec", swistak.name)
-  end
-
-  def test_loading_new_instance_should_change_dirty_attribute_original_value
-    swistak = Subscriber.find(:first, :conditions => {:nick => 'swistak'})
-    swistak.name = "Swistak Sreberkowiec"
-
-    Subscriber.update_all({:name => "Raczkowski Marcin"}, {:name => "Marcin Raczkowski"})
-
-    assert_equal({"name"=>["Marcin Raczkowski", "Swistak Sreberkowiec"]}, swistak.changes)
-    assert_equal("Swistak Sreberkowiec", swistak.name)
-  end
-
-  def test_loading_new_instance_should_remove_dirt
-    swistak = Subscriber.find(:first, :conditions => {:nick => 'swistak'})
-    swistak.name = "Swistak Sreberkowiec"
-
-    assert_equal({"name" => ["Marcin Raczkowski", "Swistak Sreberkowiec"]}, swistak.changes)
-
-    Subscriber.update_all({:name => "Swistak Sreberkowiec"}, {:name => "Marcin Raczkowski"})
-
-    assert_equal("Swistak Sreberkowiec", swistak.name)
-    assert_equal({"name"=>["Marcin Raczkowski", "Swistak Sreberkowiec"]}, swistak.changes)
-    assert swistak.name_changed?
-  end
-
-  def test_has_many_associations
-    pirate = Pirate.create!(:catchphrase => "Don' botharrr talkin' like one, savvy?")
-    pirate.birds.create!(:name => 'Posideons Killer')
-    pirate.birds.create!(:name => 'Killer bandita Dionne')
-
-    posideons, _ = pirate.birds
-
-    pirate.reload
-
-    pirate.birds_attributes = [{ :id => posideons.id, :name => 'Grace OMalley' }]
-    assert_equal 'Grace OMalley', pirate.birds.to_a.find { |r| r.id == posideons.id }.name
-  end
-
-  def test_changing_associations
-    post1 = Post.create("title" => "One post", "body" => "Posting...")
-    post2 = Post.create("title" => "Another post", "body" => "Posting... Again...")
-    comment = Comment.new("body" => "comment")
-
-    comment.post = post1
-    assert comment.save
-
-    assert_same(post1.comments.first, comment)
-
-    comment.post = post2
-    assert comment.save
-
-    assert_same(post2.comments.first, comment)
-    assert_equal(0, post1.comments.size)
-  end
-
-  def test_im_with_polymorphic_has_many_going_through_join_model_with_custom_select_and_joins
-    tag = posts(:welcome).tags.first
-    tag_with_joins_and_select = posts(:welcome).tags.add_joins_and_select.first
-    assert_same(tag, tag_with_joins_and_select)
-    assert_nothing_raised(NoMethodError, "Joins/select was not loaded") { tag.author_id }
-  end
-
-  ##############################################################################
-  # Tests checking Identity Map behavior with preloaded associations, joins,   #
-  # includes etc.                                                              #
-  ##############################################################################
-
-  def test_find_with_preloaded_associations
-    assert_queries(2) do
-      posts = Post.preload(:comments).order('posts.id')
-      assert posts.first.comments.first
-    end
-
-    # With IM we'll retrieve post object from previous query, it'll have comments
-    # already preloaded from first call
-    assert_queries(1) do
-      posts = Post.preload(:comments).order('posts.id')
-      assert posts.first.comments.first
-    end
-
-    assert_queries(2) do
-      posts = Post.preload(:author).order('posts.id')
-      assert posts.first.author
-    end
-
-    # With IM we'll retrieve post object from previous query, it'll have comments
-    # already preloaded from first call
-    assert_queries(1) do
-      posts = Post.preload(:author).order('posts.id')
-      assert posts.first.author
-    end
-
-    assert_queries(1) do
-      posts = Post.preload(:author, :comments).order('posts.id')
-      assert posts.first.author
-      assert posts.first.comments.first
-    end
-  end
-
-  def test_find_with_included_associations
-    assert_queries(2) do
-      posts = Post.includes(:comments).order('posts.id')
-      assert posts.first.comments.first
-    end
-
-    assert_queries(1) do
-      posts = Post.scoped.includes(:comments).order('posts.id')
-      assert posts.first.comments.first
-    end
-
-    assert_queries(2) do
-      posts = Post.includes(:author).order('posts.id')
-      assert posts.first.author
-    end
-
-    assert_queries(1) do
-      posts = Post.includes(:author, :comments).order('posts.id')
-      assert posts.first.author
-      assert posts.first.comments.first
-    end
-  end
-
-  def test_eager_loading_with_conditions_on_joined_table_preloads
-    posts = Post.find(:all, :select => 'distinct posts.*', :include => :author, :joins => [:comments], :conditions => "comments.body like 'Thank you%'", :order => 'posts.id')
-    assert_equal [posts(:welcome)], posts
-    assert_equal authors(:david), assert_no_queries { posts[0].author}
-    assert_same posts.first.author, Author.first
-
-    posts = Post.find(:all, :select => 'distinct posts.*', :include => :author, :joins => [:comments], :conditions => "comments.body like 'Thank you%'", :order => 'posts.id')
-    assert_equal [posts(:welcome)], posts
-    assert_equal authors(:david), assert_no_queries { posts[0].author}
-    assert_same posts.first.author, Author.first
-
-    posts = Post.find(:all, :include => :author, :joins => {:taggings => :tag}, :conditions => "tags.name = 'General'", :order => 'posts.id')
-    assert_equal posts(:welcome, :thinking), posts
-    assert_same posts.first.author, Author.first
-
-    posts = Post.find(:all, :include => :author, :joins => {:taggings => {:tag => :taggings}}, :conditions => "taggings_tags.super_tag_id=2", :order => 'posts.id')
-    assert_equal posts(:welcome, :thinking), posts
-    assert_same posts.first.author, Author.first
-  end
-
-  def test_eager_loading_with_conditions_on_string_joined_table_preloads
-    posts = assert_queries(2) do
-      Post.find(:all, :select => 'distinct posts.*', :include => :author, :joins => "INNER JOIN comments on comments.post_id = posts.id", :conditions => "comments.body like 'Thank you%'", :order => 'posts.id')
-    end
-    assert_equal [posts(:welcome)], posts
-    assert_equal authors(:david), assert_no_queries { posts[0].author}
-
-    posts = assert_queries(1) do
-      Post.find(:all, :select => 'distinct posts.*', :include => :author, :joins => ["INNER JOIN comments on comments.post_id = posts.id"], :conditions => "comments.body like 'Thank you%'", :order => 'posts.id')
-    end
-    assert_equal [posts(:welcome)], posts
-    assert_equal authors(:david), assert_no_queries { posts[0].author}
-  end
-
-  ##############################################################################
-  # Behaviour related to saving failures
-  ##############################################################################
-
-  def test_reload_object_if_save_failed
-    developer = Developer.first
-    developer.salary = 0
-
-    assert !developer.save
-
-    same_developer = Developer.first
-
-    assert_not_same  developer, same_developer
-    assert_not_equal 0, same_developer.salary
-    assert_not_equal developer.salary, same_developer.salary
-  end
-
-  def test_reload_object_if_forced_save_failed
-    developer = Developer.first
-    developer.salary = 0
-
-    assert_raise(ActiveRecord::RecordInvalid) { developer.save! }
-
-    same_developer = Developer.first
-
-    assert_not_same  developer, same_developer
-    assert_not_equal 0, same_developer.salary
-    assert_not_equal developer.salary, same_developer.salary
-  end
-
-  def test_reload_object_if_update_attributes_fails
-    developer = Developer.first
-    developer.salary = 0
-
-    assert !developer.update_attributes(:salary => 0)
-
-    same_developer = Developer.first
-
-    assert_not_same  developer, same_developer
-    assert_not_equal 0, same_developer.salary
-    assert_not_equal developer.salary, same_developer.salary
-  end
-
-  ##############################################################################
-  # Behaviour of readonly, frozen, destroyed
-  ##############################################################################
-
-  def test_find_using_identity_map_respects_readonly_when_loading_associated_object_first
-    author  = Author.first
-    readonly_comment = author.readonly_comments.first
-
-    comment = Comment.first
-    assert !comment.readonly?
-
-    assert readonly_comment.readonly?
-
-    assert_raise(ActiveRecord::ReadOnlyRecord) {readonly_comment.save}
-    assert comment.save
-  end
-
-  def test_find_using_identity_map_respects_readonly
-    comment = Comment.first
-    assert !comment.readonly?
-
-    author  = Author.first
-    readonly_comment = author.readonly_comments.first
-
-    assert readonly_comment.readonly?
-
-    assert_raise(ActiveRecord::ReadOnlyRecord) {readonly_comment.save}
-    assert comment.save
-  end
-
-  def test_find_using_select_and_identity_map
-    author_id, author = Author.select('id').first, Author.first
-
-    assert_equal author_id, author
-    assert_same author_id, author
-    assert_not_nil author.name
-
-    post, post_id = Post.first, Post.select('id').first
-
-    assert_equal post_id, post
-    assert_same post_id, post
-    assert_not_nil post.title
-  end
-
-# Currently AR is not allowing changing primary key (see Persistence#update)
-# So we ignore it. If this changes, this test needs to be uncommented.
-#  def test_updating_of_pkey
-#    assert client = Client.find(3),
-#    client.update_attribute(:id, 666)
-#
-#    assert Client.find(666)
-#    assert_same(client, Client.find(666))
-#
-#    s = Subscriber.find_by_nick('swistak')
-#    assert s.update_attribute(:nick, 'swistakTheJester')
-#    assert_equal('swistakTheJester', s.nick)
-#
-#    assert stj = Subscriber.find_by_nick('swistakTheJester')
-#    assert_same(s, stj)
-#  end
-
-end
-end
diff --git a/activerecord/test/cases/log_subscriber_test.rb b/activerecord/test/cases/log_subscriber_test.rb
index d1f0ace184..acd2fcdad4 100644
--- a/activerecord/test/cases/log_subscriber_test.rb
+++ b/activerecord/test/cases/log_subscriber_test.rb
@@ -11,8 +11,6 @@ class LogSubscriberTest < ActiveRecord::TestCase
 
   def setup
     @old_logger = ActiveRecord::Base.logger
-    @using_identity_map = ActiveRecord::IdentityMap.enabled?
-    ActiveRecord::IdentityMap.enabled = false
     Developer.primary_key
     super
     ActiveRecord::LogSubscriber.attach_to(:active_record)
@@ -22,7 +20,6 @@ class LogSubscriberTest < ActiveRecord::TestCase
     super
     ActiveRecord::LogSubscriber.log_subscribers.pop
     ActiveRecord::Base.logger = @old_logger
-    ActiveRecord::IdentityMap.enabled = @using_identity_map
   end
 
   def set_logger(logger)
@@ -103,13 +100,4 @@ class LogSubscriberTest < ActiveRecord::TestCase
   def test_initializes_runtime
     Thread.new { assert_equal 0, ActiveRecord::LogSubscriber.runtime }.join
   end
-
-  def test_log
-    ActiveRecord::IdentityMap.use do
-      Post.find 1
-      Post.find 1
-    end
-    wait
-    assert_match(/From Identity Map/, @logger.logged(:debug).last)
-  end
 end
diff --git a/activerecord/test/cases/query_cache_test.rb b/activerecord/test/cases/query_cache_test.rb
index f36f4237b1..d93478513b 100644
--- a/activerecord/test/cases/query_cache_test.rb
+++ b/activerecord/test/cases/query_cache_test.rb
@@ -107,7 +107,7 @@ class QueryCacheTest < ActiveRecord::TestCase
   end
 
   def test_find_queries
-    assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 2) { Task.find(1); Task.find(1) }
+    assert_queries(2) { Task.find(1); Task.find(1) }
   end
 
   def test_find_queries_with_cache
diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index acec230c72..91bc407d42 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -323,7 +323,7 @@ class RelationTest < ActiveRecord::TestCase
       assert posts.first.comments.first
     end
 
-    assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 2) do
+    assert_queries(2) do
       posts = Post.preload(:comments).order('posts.id')
       assert posts.first.comments.first
     end
@@ -333,12 +333,12 @@ class RelationTest < ActiveRecord::TestCase
       assert posts.first.author
     end
 
-    assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 2) do
+    assert_queries(2) do
       posts = Post.preload(:author).order('posts.id')
       assert posts.first.author
     end
 
-    assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 3) do
+    assert_queries(3) do
       posts = Post.preload(:author, :comments).order('posts.id')
       assert posts.first.author
       assert posts.first.comments.first
@@ -351,7 +351,7 @@ class RelationTest < ActiveRecord::TestCase
       assert posts.first.comments.first
     end
 
-    assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 2) do
+    assert_queries(2) do
       posts = Post.scoped.includes(:comments).order('posts.id')
       assert posts.first.comments.first
     end
@@ -361,7 +361,7 @@ class RelationTest < ActiveRecord::TestCase
       assert posts.first.author
     end
 
-    assert_queries(ActiveRecord::IdentityMap.enabled? ? 1 : 3) do
+    assert_queries(3) do
       posts = Post.includes(:author, :comments).order('posts.id')
       assert posts.first.author
       assert posts.first.comments.first
@@ -685,10 +685,8 @@ class RelationTest < ActiveRecord::TestCase
   end
 
   def test_relation_merging_with_preload
-    ActiveRecord::IdentityMap.without do
-      [Post.scoped.merge(Post.preload(:author)), Post.preload(:author).merge(Post.scoped)].each do |posts|
-        assert_queries(2) { assert posts.first.author }
-      end
+    [Post.scoped.merge(Post.preload(:author)), Post.preload(:author).merge(Post.scoped)].each do |posts|
+      assert_queries(2) { assert posts.first.author }
     end
   end
 
diff --git a/activerecord/test/support/connection.rb b/activerecord/test/support/connection.rb
index 11154c3797..c176316a05 100644
--- a/activerecord/test/support/connection.rb
+++ b/activerecord/test/support/connection.rb
@@ -12,7 +12,7 @@ module ARTest
   end
 
   def self.connect
-    puts "Using #{connection_name} with Identity Map #{ActiveRecord::IdentityMap.enabled? ? 'on' : 'off'}"
+    puts "Using #{connection_name}"
     ActiveRecord::Model.logger = ActiveSupport::Logger.new("debug.log")
     ActiveRecord::Model.configurations = connection_config
     ActiveRecord::Model.establish_connection 'arunit'