As found by @t-schroeder in pull 359, the studentquiz_comment table declares indexes on the three columns userid, questionid and usermodified even though there are already foreign keys on those columns.
Moodle automatically creates indexes where foreign keys are declares, so these manual indexes are unnecessary and inefficeint. They should be removed.
As found by @t-schroeder in pull 359, the studentquiz_comment table declares indexes on the three columns userid, questionid and usermodified even though there are already foreign keys on those columns.
Moodle automatically creates indexes where foreign keys are declares, so these manual indexes are unnecessary and inefficeint. They should be removed.