Commit d62ce1d4 authored by Mark Johnson's avatar Mark Johnson
Browse files

MDL-67681 Cache: Store coursecattree array in a single key

parent 4e41ace0
......@@ -710,17 +710,38 @@ class core_course_category implements renderable, cacheable_object, IteratorAggr
* 0 - array of ids of top-level categories (always present)
* '0i' - array of ids of top-level categories that have visible=0 (always present but may be empty array)
* $id (int) - array of ids of categories that are direct children of category with id $id. If
* category with id $id does not exist returns false. If category has no children returns empty array
* category with id $id does not exist, or category has no children, returns empty array
* $id.'i' - array of ids of children categories that have visible=0
*
* @param int|string $id
* @return mixed
*/
protected static function get_tree($id) {
$all = self::get_cached_cat_tree();
if (is_null($all) || !isset($all[$id])) {
// Could not get or rebuild the tree, or requested a non-existant ID.
return [];
} else {
return $all[$id];
}
}
/**
* Return the course category tree.
*
* Returns the category tree array, from the cache if available or rebuilding the cache
* if required. Uses locking to prevent the cache being rebuilt by multiple requests at once.
*
* @return array|null The tree as an array, or null if rebuilding the tree failed due to a lock timeout.
* @throws coding_exception
* @throws dml_exception
* @throws moodle_exception
*/
private static function get_cached_cat_tree() : ?array {
$coursecattreecache = cache::make('core', 'coursecattree');
$rv = $coursecattreecache->get($id);
if ($rv !== false) {
return $rv;
$all = $coursecattreecache->get('all');
if ($all !== false) {
return $all;
}
// Might need to rebuild the tree. Put a lock in place to ensure other requests don't try and do this in parallel.
$lockfactory = \core\lock\lock_config::get_lock_factory('core_coursecattree');
......@@ -728,26 +749,22 @@ class core_course_category implements renderable, cacheable_object, IteratorAggr
course_modinfo::COURSE_CACHE_LOCK_WAIT, course_modinfo::COURSE_CACHE_LOCK_EXPIRY);
if ($lock === false) {
// Couldn't get a lock to rebuild the tree.
return [];
return null;
}
$rv = $coursecattreecache->get($id);
if ($rv !== false) {
$all = $coursecattreecache->get('all');
if ($all !== false) {
// Tree was built while we were waiting for the lock.
$lock->release();
return $rv;
return $all;
}
// Re-build the tree.
try {
$all = self::rebuild_coursecattree_cache_contents();
$coursecattreecache->set_many($all);
$coursecattreecache->set('all', $all);
} finally {
$lock->release();
}
if (array_key_exists($id, $all)) {
return $all[$id];
}
// Requested non-existing category.
return array();
return $all;
}
/**
......@@ -1364,7 +1381,7 @@ class core_course_category implements renderable, cacheable_object, IteratorAggr
while (count($walk) > 0) {
$catid = array_pop($walk);
$directchildren = self::get_tree($catid);
if ($directchildren !== false && count($directchildren) > 0) {
if (count($directchildren) > 0) {
$walk = array_merge($walk, $directchildren);
$children = array_merge($children, $directchildren);
}
......
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