Performance compare (start test BEFORE UPGRADE or revert commits from this issue): Create several course categories, courses in them and modules with files Enrol a teacher in some of these courses Hide some course categories and unhide courses in them so that teacher is enrolled in a course that is inside a hidden category Login as a teacher and open a file manager anywhere (for example, create a new resource and insert a link in an editor) Add 'logall'=>true to the dboptions in config.php As a teacher open "Server files" repository and navigate to top level. Check the number of new records in the mdl_log_queries table - remember this number Remove logall and truncate the mdl_log_queries table UPGRADE As the same teacher navigate to the same page Add 'logall'=>true to the dboptions in config.php As a teacher open "Server files" repository and navigate to top level. Check the number of new records in the mdl_log_queries table - it should be significantly less than before upgrade Regression test - browse around "Server files" repository, make sure that you can see all courses where you are enrolled and files inside them. If category containing your courses is hidden you should see these courses on the lowest level of the category that you can access (or system) Important to perform all tests as a TEACHER - admins bypass all checks and students do not have access to "Server files" repository