From 2af7d0d8d01bc9c4aace3e9e44ffcd04e860c598 Mon Sep 17 00:00:00 2001 From: Michael Aherne Date: Wed, 8 Feb 2012 14:41:38 +0000 Subject: [PATCH] MDL-31495 Performance improvement in question engine upgrade SQL --- question/engine/upgrade/upgradelib.php | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/question/engine/upgrade/upgradelib.php b/question/engine/upgrade/upgradelib.php index 8c6e175f548..b11ef48f49d 100644 --- a/question/engine/upgrade/upgradelib.php +++ b/question/engine/upgrade/upgradelib.php @@ -155,19 +155,19 @@ class question_engine_attempt_upgrader { $quizattemptsrs = $DB->get_recordset_select('quiz_attempts', $where, $params, 'uniqueid'); $questionsessionsrs = $DB->get_recordset_sql(" - SELECT * - FROM {question_sessions} - WHERE attemptid IN ( - SELECT uniqueid FROM {quiz_attempts} WHERE $where) - ORDER BY attemptid, questionid + SELECT s.* + FROM {question_sessions} s + JOIN {quiz_attempts} a ON (attemptid = uniqueid) + WHERE $where + ORDER BY attemptid, questionid ", $params); $questionsstatesrs = $DB->get_recordset_sql(" - SELECT * - FROM {question_states} - WHERE attempt IN ( - SELECT uniqueid FROM {quiz_attempts} WHERE $where) - ORDER BY attempt, question, seq_number, id + SELECT s.* + FROM {question_states} s + JOIN {quiz_attempts} ON (s.attempt = uniqueid) + WHERE $where + ORDER BY s.attempt, question, seq_number, s.id ", $params); $datatodo = $quizattemptsrs && $questionsessionsrs && $questionsstatesrs; -- 2.36.1