Require request specs when testing N+1 for controllers

1 files changed, 7 insertions, 0 deletions

diff --git a/doc/development/query_recorder.md b/doc/development/query_recorder.md
index a6b60149ea4..3787e2ef187 100644
--- a/doc/development/query_recorder.md
+++ b/doc/development/query_recorder.md
@@ -36,6 +36,13 @@ it "avoids N+1 database queries" do
 end
 ```
 
+## Use request specs instead of controller specs
+
+Use a [request spec](https://gitlab.com/gitlab-org/gitlab-ce/tree/master/spec/requests) when writing a N+1 test on the controller level.
+
+Controller specs should not be used to write N+1 tests as the controller is only initialized once per example.
+This could lead to false successes where subsequent "requests" could have queries reduced (e.g. because of memoization).
+
 ## Finding the source of the query
 
 It may be useful to identify the source of the queries by looking at the call backtrace.