Regression in login performance with enrol_database

Before applying the patch: Generate a large database for external authentication. You can do so using this repo: https://github.com/andrewnicols/mdl_auth_db - I created 2500 users, and 2400 courses, with a max users / course of 1000 - you don't need this many. Perhaps go for 1000, 1000, 1000 at most. Ensure that enrol_database, and auth_db are configured correctly and have been run recently Run database plugin CLI to test sync_enrolments() Ensure that PERF_DB and friends are enabled Choose a user and find their ID Download https://gist.github.com/andrewnicols/75ef940135128eae2b22 to test.php and update user ID run test.php several times and note the run times + DB stats Apply the patch run test.php several times and note the run times + DB stats Compare: run times - they should be faster DB reads - they should be less than / equal DB writes - they should be roughly equal (there may be 1 or 2 different due to caching/sessions/etc)