From 21c92cf39d719a913cd9e29474c04781e9cd72ef Mon Sep 17 00:00:00 2001 From: cash Date: Sat, 13 Apr 2013 15:05:40 -0400 Subject: Fixes #4978 integrates LRU cache for db query cache --- engine/lib/database.php | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) (limited to 'engine/lib/database.php') 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: * - * $DB_QUERY_CACHE[$query] => array(result1, result2, ... resultN) + * $DB_QUERY_CACHE[query hash] => array(result1, result2, ... resultN) * + * @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'); } } -- cgit v1.2.3