Before the patch Check out a version before this patch (e.g. " git checkout 1a7f8e7eed3 ") Go to admin > development > debugging and turn perfdebug on. Or if using MDK: " mdk run mindev " Create a test course that includes at least 10 participants Create an assignment with either "Online text" or "File submissions" Enter the assignment and hit the "View all submissions" link to view the grading page. Grade at least 5 students: On the grading page, enter a grade Save changes You'll see a " Comments " area (not the " Feedback comments "). Expand the comments area. Enter a comment and save the changes and do the same for the other students to be graded. After grading the students, press " View all submissions " Reload the assignment grading page about two times. Take note of the "DB reads" value at the bottom of the page. Apply the patch Check out the version with this patch applied. Reload the assignment grading page a couple of times. Take note of the DB reads value at the bottom of the page. Confirm that they are lower than the number before the patch. Create another assignment instance Grade some students and add some comments. Confirm that the grading table shows the comments correctly for the students. Go to the first assignment instance Confirm that the grading table shows the comments correctly for the students.