1 files changed, 14 insertions, 12 deletions
diff --git a/activerecord/lib/active_record/railtie.rb b/activerecord/lib/active_record/railtie.rb
index aceb70bc45..64eac3aca7 100644
--- a/activerecord/lib/active_record/railtie.rb
+++ b/activerecord/lib/active_record/railtie.rb
@@ -112,7 +112,18 @@ module ActiveRecord
               `config/application.rb` file and any `mass_assignment_sanitizer` options
               from your `config/environments/*.rb` files.
 
-              See http://guides.rubyonrails.org/security.html#mass-assignment for more information
+              See http://guides.rubyonrails.org/security.html#mass-assignment for more information.
+            EOF
+          end
+
+          unless app.config.active_record.delete(:auto_explain_threshold_in_seconds).nil?
+            ActiveSupport::Deprecation.warn <<-EOF.strip_heredoc, []
+              The Active Record auto explain feature has been removed.
+
+              To disable this message remove the `active_record.auto_explain_threshold_in_seconds`
+              option from the `config/environments/*.rb` config file.
+
+              See http://guides.rubyonrails.org/4_0_release_notes.html for more information.
             EOF
           end
 
@@ -124,7 +135,7 @@ module ActiveRecord
               To disable this message remove the `observers` option from your
               `config/application.rb` or from your initializers.
 
-              See http://guides.rubyonrails.org/4_0_release_notes.html for more information
+              See http://guides.rubyonrails.org/4_0_release_notes.html for more information.
             EOF
           end
         ensure
@@ -141,20 +152,11 @@ module ActiveRecord
     # and then establishes the connection.
     initializer "active_record.initialize_database" do |app|
       ActiveSupport.on_load(:active_record) do
-        unless ENV['DATABASE_URL']
-          self.configurations = app.config.database_configuration
-        end
+        self.configurations = app.config.database_configuration
         establish_connection
       end
     end
 
-    initializer "active_record.validate_explain_support" do |app|
-      if app.config.active_record[:auto_explain_threshold_in_seconds] &&
-        !ActiveRecord::Base.connection.supports_explain?
-        warn "auto_explain_threshold_in_seconds is set but will be ignored because your adapter does not support this feature. Please unset the configuration to avoid this warning."
-      end
-    end
-
     # Expose database runtime to controller for logging.
     initializer "active_record.log_runtime" do |app|
       require "active_record/railties/controller_runtime"