4 files changed, 16 insertions, 11 deletions
diff --git a/config.ru b/config.ru
index c4bef72308e..7b15939c6ff 100644
--- a/config.ru
+++ b/config.ru
@@ -23,6 +23,6 @@ warmup do |app|
 end
 
 map ENV['RAILS_RELATIVE_URL_ROOT'] || "/" do
-  use Gitlab::ReleaseController
+  use Gitlab::Middleware::ReleaseEnv
   run Gitlab::Application
 end
diff --git a/lib/gitlab/middleware/release_controller.rb b/lib/gitlab/middleware/release_controller.rb
deleted file mode 100644
index a21d718d51c..00000000000
--- a/lib/gitlab/middleware/release_controller.rb
+++ /dev/null
@@ -1,9 +0,0 @@
-module Gitlab
-  module Middleware
-    ReleaseController = Struct.new(:app) do
-      def call(env)
-        app.call(env).tap { env.delete('action_controller.instance') }
-      end
-    end
-  end
-end
diff --git a/lib/gitlab/middleware/release_env.rb b/lib/gitlab/middleware/release_env.rb
new file mode 100644
index 00000000000..f8d0a135965
--- /dev/null
+++ b/lib/gitlab/middleware/release_env.rb
@@ -0,0 +1,14 @@
+module Gitlab
+  module Middleware
+    # Some of middleware would hold env for no good reason even after the
+    # request had already been processed, and we could not garbage collect
+    # them due to this. Put this middleware as the first middleware so that
+    # it would clear the env after the request is done, allowing GC gets a
+    # chance to release memory for the last request.
+    ReleaseEnv = Struct.new(:app) do
+      def call(env)
+        app.call(env).tap { env.clear }
+      end
+    end
+  end
+end
diff --git a/spec/lib/gitlab/middleware/release_controller_spec.rb b/spec/lib/gitlab/middleware/release_env_spec.rb
index 854bac6e751..657b705502a 100644
--- a/spec/lib/gitlab/middleware/release_controller_spec.rb
+++ b/spec/lib/gitlab/middleware/release_env_spec.rb
@@ -1,6 +1,6 @@
 require 'spec_helper'
 
-describe Gitlab::Middleware::ReleaseController do
+describe Gitlab::Middleware::ReleaseEnv do
   let(:inner_app) { double(:app) }
   let(:app) { described_class.new(inner_app) }
   let(:env) { { 'action_controller.instance' => 'something' } }