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-rw-r--r--engine/lib/database.php29
1 files changed, 15 insertions, 14 deletions
diff --git a/engine/lib/database.php b/engine/lib/database.php
index b41eb4cda..3553d787d 100644
--- a/engine/lib/database.php
+++ b/engine/lib/database.php
@@ -12,18 +12,19 @@
/**
* Query cache for all queries.
*
- * Each query and its results are stored in this array as:
+ * Each query and its results are stored in this cache as:
* <code>
- * $DB_QUERY_CACHE[$query] => array(result1, result2, ... resultN)
+ * $DB_QUERY_CACHE[query hash] => array(result1, result2, ... resultN)
* </code>
+ * @see elgg_query_runner() for details on the hash.
*
- * @warning be array this var may be an array or ElggStaticVariableCache depending on when called :(
+ * @warning Elgg used to set this as an empty array to turn off the cache
*
- * @global ElggStaticVariableCache|array $DB_QUERY_CACHE
+ * @global ElggLRUCache|null $DB_QUERY_CACHE
* @access private
*/
global $DB_QUERY_CACHE;
-$DB_QUERY_CACHE = array();
+$DB_QUERY_CACHE = null;
/**
* Queries to be executed upon shutdown.
@@ -127,9 +128,8 @@ function establish_db_link($dblinkname = "readwrite") {
// Set up cache if global not initialized and query cache not turned off
if ((!$DB_QUERY_CACHE) && (!$db_cache_off)) {
- // @todo everywhere else this is assigned to array(), making it dangerous to call
- // object methods on this. We should consider making this an plain array
- $DB_QUERY_CACHE = new ElggStaticVariableCache('db_query_cache');
+ // @todo if we keep this cache in 1.9, expose the size as a config parameter
+ $DB_QUERY_CACHE = new ElggLRUCache(200);
}
}
@@ -404,11 +404,9 @@ function elgg_query_runner($query, $callback = null, $single = false) {
// Is cached?
if ($DB_QUERY_CACHE) {
- $cached_query = $DB_QUERY_CACHE[$hash];
-
- if ($cached_query !== FALSE) {
+ if (isset($DB_QUERY_CACHE[$hash])) {
elgg_log("DB query $query results returned from cache (hash: $hash)", 'NOTICE');
- return $cached_query;
+ return $DB_QUERY_CACHE[$hash];
}
}
@@ -531,10 +529,13 @@ function delete_data($query) {
*/
function _elgg_invalidate_query_cache() {
global $DB_QUERY_CACHE;
- if ($DB_QUERY_CACHE) {
- /* @var ElggStaticVariableCache $DB_QUERY_CACHE */
+ if ($DB_QUERY_CACHE instanceof ElggLRUCache) {
$DB_QUERY_CACHE->clear();
elgg_log("Query cache invalidated", 'NOTICE');
+ } elseif ($DB_QUERY_CACHE) {
+ // In case someone sets the cache to an array and primes it with data
+ $DB_QUERY_CACHE = array();
+ elgg_log("Query cache invalidated", 'NOTICE');
}
}