(PECL memcached >= 0.1.0)
Memcached::deleteByKey — Delete an item from a specific server
$server_key
   , string $key
   [, int $time = 0
  ] )
   Memcached::deleteByKey() is functionally equivalent to
   Memcached::delete(), except that the free-form
   server_key can be used to map the
   key to a specific server.
  
server_keyThe key identifying the server to store the value on or retrieve it from. Instead of hashing on the actual key for the item, we hash on the server key when deciding which memcached server to talk to. This allows related items to be grouped together on a single server for efficiency with multi operations.
keyThe key to be deleted.
timeThe amount of time the server will wait to delete the item.
   Returns TRUE on success or FALSE on failure.
   The Memcached::getResultCode() will return
   Memcached::RES_NOTFOUND if the key does not exist.