Testing that this change does not cause any regressions will be covered by unit tests. To test that this change acually fixes the performance problem requies a Moodle site with a large number of questions and quizzes already set up. So, we could just rely on santoshnagargoje 's testing of my patch, reported below. Or, if you have access to such a site, you can test as follows: As teacher (or admin) create a Quiz in a test course. Go to the 'Questions' page in the secondary nav, so you can add questions. Choose Add -> A new question, to add a True False question. (Question type does not matter, but TF is fast to create.) Again, choose, Add -> A new question, to add a True False question. Verify that when you click the 'Save changse' button to finish creating the question, there is not a long delay. (Before this fix, with a large questoin bank and lots of quizzes, there was - probably good if you were able to reproduce that on your test site before trying to verify this fix.)