When a client A is connected openfire server, if client A sudden disconnection. Server is unable to be detected immediately.
And this time the question is: When the client B A message to the client is still, in fact, A has been disconnected, this time the message has been lost.
In openfire service from there to the client sends a ping message mechanism, but if ping message transmission time interval is too small, the server will have a great impact on the efficiency. If the ping test time is too long, then the client disconnects that moment (may be a few seconds) can not receive messages. Does everyone on this question did not have any good treatment options.