Improve performance of get_all_groups_of_choices

Author: Noemie Ariste

locallib.php

@@ -765,14 +765,17 @@ private function process_action_manual_allocation() {
      * @return array of group ids used in rateable choices
      */
     public function get_all_groups_of_choices(): array {
-        $rateablechoiceswithgrouprestrictions = array_filter($this->get_rateable_choices(),
-                fn($choice) => !empty($choice->usegroups) && !empty($this->get_choice_groups($choice->id)));
-        $rateablechoiceids = array_map(fn($choice) => $choice->id, $rateablechoiceswithgrouprestrictions);
-        $groupids = [];
-        foreach ($rateablechoiceids as $choiceid) {
-            $groupids = array_merge($groupids, array_map(fn($group) => $group->id, $this->get_choice_groups($choiceid)));
-        }
-        return array_unique($groupids);
+        global $DB;
+
+        $sql = 'SELECT DISTINCT g.id
+                           FROM {ratingallocate_group_choices} gc
+                           JOIN {ratingallocate_choices} rc on rc.id = gc.choiceid
+                           JOIN {groups} g ON gc.groupid=g.id
+                          WHERE rc.ratingallocateid=:id';
+
+        $groupids = $DB->get_fieldset_sql($sql, ['id' => $this->ratingallocateid]);
+
+        return $groupids;
     }
 
     /**