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MDL-55776 enrol: Optimise enrolled users listing.

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Here we optimise SQL queries for enrolled users list. Expensive subquery is
replaced with faster LEFT JOIN and the whole groups filtering component is
aded on demand.
This commit is contained in:
Ruslan Kabalin
2016-09-19 23:48:41 +02:00
committed by Eloy Lafuente (stronk7)
parent 3df86df503
commit bfe06f7600
1 changed files with 12 additions and 14 deletions
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enrol/locallib.php
+12 -14
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@@ -171,13 +171,12 @@ class course_enrolment_manager {
$sqltotal = "SELECT COUNT(DISTINCT u.id)
FROM {user} u
JOIN {user_enrolments} ue ON (ue.userid = u.id AND ue.enrolid $instancessql)
JOIN {enrol} e ON (e.id = ue.enrolid)
LEFT JOIN {groups_members} gm ON u.id = gm.userid AND gm.groupid IN (
SELECT g.id
FROM {groups} g
WHERE g.courseid = e.courseid
)
WHERE $filtersql";
JOIN {enrol} e ON (e.id = ue.enrolid)";
if ($this->groupfilter) {
$sqltotal .= " LEFT JOIN ({groups_members} gm JOIN {groups} g ON (g.id = gm.groupid))
ON (u.id = gm.userid AND g.courseid = e.courseid)";
}
$sqltotal .= "WHERE $filtersql";
$this->totalusers = (int)$DB->count_records_sql($sqltotal, $params);
}
return $this->totalusers;
@@ -245,13 +244,12 @@ class course_enrolment_manager {
FROM {user} u
JOIN {user_enrolments} ue ON (ue.userid = u.id AND ue.enrolid $instancessql)
JOIN {enrol} e ON (e.id = ue.enrolid)
LEFT JOIN {user_lastaccess} ul ON (ul.courseid = e.courseid AND ul.userid = u.id)
LEFT JOIN {groups_members} gm ON u.id = gm.userid AND gm.groupid IN (
SELECT g.id
FROM {groups} g
WHERE g.courseid = e.courseid
)
WHERE $filtersql
LEFT JOIN {user_lastaccess} ul ON (ul.courseid = e.courseid AND ul.userid = u.id)";
if ($this->groupfilter) {
$sql .= " LEFT JOIN ({groups_members} gm JOIN {groups} g ON (g.id = gm.groupid))
ON (u.id = gm.userid AND g.courseid = e.courseid)";
}
$sql .= "WHERE $filtersql
ORDER BY $sort $direction";
$this->users[$key] = $DB->get_records_sql($sql, $params, $page*$perpage, $perpage);
}