Statistics in the Moodle 4.0 question bank use many DB queries causing performance problems

Setting up a test course. Make sure cron task is set up and works. (Otherwise we can run ' sudo -u www-data php admin/cli/cron.php ' manually ) Log in as admin user. Go to {moodle.url}/admin/tool/task/scheduledtasks.php and  set '\quiz_statistics\task\quiz_statistics_recalculate'   to run every minute. Create a course Create a quiz in the course Add 2 questions to the quiz create a user and enrol the user to the course with student role Scheduled task testing  Log in with the student account created above Finish an attempt on the quiz Expected: Wait for 1 minute, or run the cron manually Run the following query: ' select * from mdl_quiz_statistics;' There should be one record, note the time modified of the records Log in as admin Go to Course > Question bank: {moodle.url}/question/edit.php?courseid={courseid } Run the query in step 2 again, check that there is still one record and the time modified is unchanged. This implies the the question bank view does not trigger re-calculation, and hence use the values calculated by scheduled tasks. Recalculation testing  Log in with the student account Finish another attempt on the quiz Expected: Wait for 1 minute, or run the cron manually Run the following query: 'select * from mdl_quiz_statistics;' There should be only one record, but the time modified is now different. That implies the stats has been recalculated