Memcache::flush Flush all existing items at the server boolMemcache::flush Memcache::flush immediately invalidates all existing items. Memcache::flush doesn't actually free any resources, it only marks all the items as expired, so occupied memory will be overwritten by new items. Also you can use memcache_flush function. See example below. connect('memcache_host', 11211); $memcache_obj->flush(); ?> ]]> &return.success;