public static function getCachedQueryResults(Criteria $criteria, $queryType, $peerClassName, &$cacheKey, &$queryDB)
{
if (!kConf::get("query_cache_enabled")) {
return null;
}
// if the criteria has an empty IN, no need to go to the DB or memcache - return an empty array
foreach ($criteria->getMap() as $criterion) {
if (in_array(Criterion::ODER, $criterion->getConjunctions())) {
continue;
}
if ($criterion->getComparison() == Criteria::IN && !$criterion->getValue()) {
KalturaLog::debug("kQueryCache: criteria has empty IN, returning empty result set, peer={$peerClassName}");
return array();
}
}
// initialize
$invalidationKeyRules = call_user_func(array($peerClassName, 'getCacheInvalidationKeys'));
$invalidationKeys = self::getInvalidationKeysForQuery($invalidationKeyRules, $criteria);
if (!$invalidationKeys) {
return null;
}
self::initGlobalMemcache();
if (self::$s_memcacheQueries === null) {
return null;
}
// build memcache query
foreach ($invalidationKeys as $index => $invalidationKey) {
$invalidationKeys[$index] = self::CACHE_PREFIX_INVALIDATION_KEY . $invalidationKey;
}
$keysToGet = $invalidationKeys;
$keysToGet[] = self::DONT_CACHE_KEY;
$queryStart = microtime(true);
$cacheResult = self::$s_memcacheKeys->multiGet($keysToGet);
KalturaLog::debug("kQueryCache: keys query took " . (microtime(true) - $queryStart) . " seconds");
if ($cacheResult === false) {
KalturaLog::debug("kQueryCache: failed to query keys memcache, not using query cache");
return null;
}
// don't cache the result if the 'dont cache' flag is enabled
$cacheQuery = true;
if (array_key_exists(self::DONT_CACHE_KEY, $cacheResult)) {
if ($cacheResult[self::DONT_CACHE_KEY]) {
KalturaLog::debug("kQueryCache: dontCache key is set -> not caching the result");
if (class_exists('KalturaResponseCacher')) {
KalturaResponseCacher::disableConditionalCache();
}
$cacheQuery = false;
}
unset($cacheResult[self::DONT_CACHE_KEY]);
}
// check whether we should query the master
$queryDB = self::QUERY_DB_SLAVE;
$currentTime = time();
foreach ($cacheResult as $invalidationKey => $invalidationTime) {
if ($currentTime < $invalidationTime + self::QUERY_MASTER_TIME_MARGIN_SEC) {
KalturaLog::debug("kQueryCache: changed recently -> query master, peer={$peerClassName}, invkey={$invalidationKey} querytime={$currentTime} invtime={$invalidationTime}");
$queryDB = self::QUERY_DB_MASTER;
if ($currentTime < $invalidationTime + self::INVALIDATION_TIME_MARGIN_SEC) {
return null;
// The query won't be cached since cacheKey is null, it's ok cause it won't be used anyway
}
}
}
if (class_exists('KalturaResponseCacher')) {
$invalidationTime = 0;
if ($cacheResult) {
$invalidationTime = max($cacheResult);
}
KalturaResponseCacher::addInvalidationKeys($invalidationKeys, $invalidationTime);
}
// check whether we have a valid cached query
$origCacheKey = self::CACHE_PREFIX_QUERY . $queryType . md5(serialize($criteria) . self::CACHE_VERSION);
if ($cacheQuery) {
$cacheKey = $origCacheKey;
}
$queryStart = microtime(true);
$queryResult = self::$s_memcacheQueries->get($origCacheKey);
KalturaLog::debug("kQueryCache: query took " . (microtime(true) - $queryStart) . " seconds");
if (!$queryResult) {
KalturaLog::debug("kQueryCache: cache miss, peer={$peerClassName}, key={$origCacheKey}");
return null;
}
list($queryResult, $queryTime, $debugInfo) = $queryResult;
$existingInvKeys = array();
foreach ($cacheResult as $invalidationKey => $invalidationTime) {
$existingInvKeys[] = "{$invalidationKey}:{$invalidationTime}";
if ($queryTime < $invalidationTime + self::INVALIDATION_TIME_MARGIN_SEC) {
KalturaLog::debug("kQueryCache: cached query invalid, peer={$peerClassName}, key={$origCacheKey}, invkey={$invalidationKey} querytime={$queryTime} debugInfo={$debugInfo} invtime={$invalidationTime}");
return null;
}
}
// return from memcache
$existingInvKeys = implode(',', $existingInvKeys);
KalturaLog::debug("kQueryCache: returning from memcache, peer={$peerClassName}, key={$origCacheKey} queryTime={$queryTime} debugInfo={$debugInfo} invkeys=[{$existingInvKeys}]");
return $queryResult;
}