L-electron-Rare/moodle
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

New cross-db version of the big union query used by get_my_courses() function.

Browse Source 
I've tested both the "IN" subquery and the "FROM" subquery and, under sites
with more courses, the "FROM" one seems to perform slightly better. MDL-9381

Merged from MOODLE_18_STABLE
This commit is contained in:
stronk7
2007-07-22 00:56:42 +00:00
parent 23207a1a6a
commit ae7dc0d1e0
1 changed files with 40 additions and 32 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/datalib.php
+40 -32
View File
@@ -682,7 +682,7 @@ function get_courses_page($categoryid="all", $sort="c.sortorder ASC", $fields="c
*/
function get_my_courses($userid, $sort=NULL, $fields=NULL, $doanything=false,$limit=0) {
global $USER;
global $CFG, $USER;
// Default parameters
$d_sort = 'visible DESC,sortorder ASC';
@@ -744,37 +744,45 @@ function get_my_courses($userid, $sort=NULL, $fields=NULL, $doanything=false,$li
// However for a typical student on a large system this can reduce the
// number of courses considered from around 2,000 to around 2, with corresponding
// reduction in the number of queries needed.
global $CFG;
$rs=get_recordset_sql("
SELECT
$fields
FROM
{$CFG->prefix}role_assignments ra
INNER JOIN {$CFG->prefix}context x ON x.id=ra.contextid
INNER JOIN {$CFG->prefix}course c ON x.instanceid=c.id AND x.contextlevel=50
WHERE
ra.userid=$userid
UNION
SELECT
$fields
FROM
{$CFG->prefix}role_assignments ra
INNER JOIN {$CFG->prefix}context x ON x.id=ra.contextid
INNER JOIN {$CFG->prefix}course_categories a ON (a.path LIKE ".sql_concat("'%/'", 'x.instanceid', "'/%'")." OR a.id=x.instanceid) AND x.contextlevel=40
INNER JOIN {$CFG->prefix}course c ON c.category=a.id
WHERE
ra.userid=$userid
UNION
SELECT
$fields
FROM
{$CFG->prefix}role_capabilities ca
INNER JOIN {$CFG->prefix}context x ON x.id=ca.contextid AND x.contextlevel=50
INNER JOIN {$CFG->prefix}course c ON c.id=x.instanceid
WHERE
ca.contextid <> {$sitecontext->id} AND ca.capability='moodle/course:view'
ORDER BY $sort");
}
$rs=get_recordset_sql("
SELECT $fields
FROM {$CFG->prefix}course c, (
SELECT
c.id
FROM
{$CFG->prefix}role_assignments ra
INNER JOIN {$CFG->prefix}context x ON x.id = ra.contextid
INNER JOIN {$CFG->prefix}course c ON x.instanceid = c.id
WHERE
ra.userid = $userid AND
x.contextlevel = 50
UNION
SELECT
c.id
FROM
{$CFG->prefix}role_assignments ra
INNER JOIN {$CFG->prefix}context x ON x.id = ra.contextid
INNER JOIN {$CFG->prefix}course_categories a ON a.path LIKE ".sql_concat("'%/'", 'x.instanceid', "'/%'")." OR x.instanceid = a.id
INNER JOIN {$CFG->prefix}course c ON c.category = a.id
WHERE
ra.userid = $userid AND
x.contextlevel = 40
UNION
SELECT
c.id
FROM
{$CFG->prefix}role_capabilities ca
INNER JOIN {$CFG->prefix}context x ON x.id = ca.contextid
INNER JOIN {$CFG->prefix}course c ON c.id = x.instanceid
WHERE
ca.capability = 'moodle/course:view' AND
ca.contextid != {$sitecontext->id} AND
x.contextlevel = 50
) cids
WHERE c.id = cids.id
ORDER BY $sort"
);
}
if ($rs && $rs->RecordCount() > 0) {
while ($course = rs_fetch_next_record($rs)) {