(PECL memcached >= 0.1.0)
Memcached::appendByKey — Append data to an existing item on a specific server
Memcached::appendByKey() is functionally equivalent to Memcached::append, except that the free-form server_key can be used to map the key to a specific server.
The key identifying the server where the item is.
The key of the item to append the data to.
The string to append.
如果成功则返回 TRUE,失败则返回 FALSE。 The Memcached::getResultCode will return Memcached::RES_NOTSTORED if the key does not exist.