MDL-77965 Filter columns to only those used

This stops Oracle from having to try to compare text columns.
NeillM · Feb 22, 2024 · 585f8bb · 585f8bb
1 parent ee77acd
commit 585f8bb
Showing 1 changed file with 9 additions and 2 deletions.
diff --git a/mod/quiz/classes/privacy/provider.php b/mod/quiz/classes/privacy/provider.php
@@ -493,10 +493,17 @@ protected static function export_quiz_attempts(approved_contextlist $contextlist
             $userid
         );
 
+        // The layout column causes the union in the following query to fail on Oracle, it also appears to not be used.
+        // So we can filter the return values to be only those used to generate the data, this will have the benefit
+        // improving performance on all databases as we will no longer be returning a text field for each row.
+        $attemptfields = 'qa.id, qa.quiz, qa.userid, qa.attempt, qa.uniqueid, qa.preview, qa.state, qa.timestart, ' .
+            'qa.timefinish, qa.timemodified, qa.timemodifiedoffline, qa.timecheckstate, qa.sumgrades, ' .
+            'qa.gradednotificationsenttime';
+
         $sql = "SELECT
                     c.id AS contextid,
                     cm.id AS cmid,
-                    qa.*
+                    $attemptfields
                   FROM {context} c
                   JOIN {course_modules} cm ON cm.id = c.instanceid AND c.contextlevel = :contextlevel1
                   JOIN {modules} m ON m.id = cm.module AND m.name = 'quiz'
@@ -508,7 +515,7 @@ protected static function export_quiz_attempts(approved_contextlist $contextlist
                 SELECT
                     c.id AS contextid,
                     cm.id AS cmid,
-                    qa.*
+                    $attemptfields
                   FROM {context} c
                   JOIN {course_modules} cm ON cm.id = c.instanceid AND c.contextlevel = :contextlevel2
                   JOIN {modules} m ON m.id = cm.module AND m.name = 'quiz'