[ http://issues.apache.org/jira/browse/DIRMINA-246?page=comments#action_12430418 ] Niklas Therning commented on DIRMINA-246: -----------------------------------------
Maybe I should have explained a bit more in depth. :) Each SocketAcceptor starts an internal worker thread which handles incoming connections on the ports you bind to. When a new connection is established the worker thread will wrap it in a MINA Session object and call sessionCreated() on its filter chain which ultimately is handled by your IoHandler implementation. It is important to note that sessionCreated() will always be called within this worker thread, even if you have a ThreadPoolFilter in your filter chain. After the call to sessionCreated() the worker thread will hand over the new MINA Session to a SocketIoProcessor which handles all other events on the session. The SocketIoProcessor has its own internal worker thread which will fire events like messageReceived and messageSent when bytes have been received and sent on a connection. It will also handle calls to session.close(). Since you call session.close() from within the SocketAcceptor's worker thread the session has not yet been added to a SocketIoProcessor. Remember that it is the SocketIoProcessor which handles the close() call (and notifies the CloseFuture). If you also join() on the CloseFuture returned by session.close() your code will hang until the session has been added to the SocketIoProcessor. But your code also blocks the thread which is responsible for adding the session the SocketIoProcessor. The call to join() will never return! unbindAll() doesn't return until all ports have been unbound by the SocketAcceptor's worker thread. But the worker is hanging indefinitely on the CloseFuture. This is why your server freezes. I hope this wasn't too much information! :) My suggestion is that you avoid the join(). In fact, in most cases we discourage users to make blocking calls in any of the IoHandler callbacks. This is particularly important for sessionCreated() since it is called from within the acceptor's worker thread even if there's a ThreadPoolFilter in the filter chain. > MINA (0.9.4) blocks with unbindAll while serveral clients were connected > ------------------------------------------------------------------------ > > Key: DIRMINA-246 > URL: http://issues.apache.org/jira/browse/DIRMINA-246 > Project: Directory MINA > Issue Type: Bug > Affects Versions: 0.9.4 > Environment: Windows XP, JDK 1.5.06 > Reporter: Frederic Bregier > Attachments: 2dumps.txt > > > After a post on the mailing list, as asked, I post a JIRA request: > I wanted to offer a function to shutdown gracefully the server, > that is to say that the server doesn't accept new connection, > but does let already connected client to finished correctly > their session (which are multi messages related). > In the beginning I used: > - setDisconnectOnUnbind(false) > - unbindAll() > - wait in my business logic that all already connected users shutting down > - setDisconnectOnUnbind(true) > - unbindAll() > I've got a lot of freeze (using 6 clients making a lot of messages) > in either the first or the second unbindAll(). > So I simplify like this: > - I am waiting in my business logic that all already connected users shutting > down and does not accept new connection by hand (business logic). > To make that, when I have the global static boolean shutdown as True, > every new connexion are immediately closed by the server. > Also, every pending connexion will finished their session, and when > finished, the server also closed the connexion. > The session used to send the shutdown order is closed immediately > after receiving the order. > - setDisconnectOnUnbind(true) > - unbindAll() > I still have easily a freeze in the server during the call to > unbindAll(). > - If I have only 1 client, unbindAll is never blocking. > - If I have 2 to 6 clients, making their stuff, they all disconnected > correctly from the server (the server is closing the session itself). > I saw that every clients are getting correctly the closed event. > But the server often blocks during the call of unbindAll(). > I am no able at this time to see where is the problem in MINA. > Everything seems ok for me from the point of vue of a programmer > using MINA. But I surely make some mistakes since it seems > that I am the only one to have this problem. > Could it be related to the fact that this is the server that is > forcing the close of the session ? > The only thing I can tell now is that it is blocling during the > call of unbindAll() in the server part. > I attached two thread dumps in one file : the first is when the server is > completely started and functionnal, the second after it blocks. > I generate these dump using jdb since I was not able to generate them > directly). > I hope this can clarify where is the problem. > Frederic Bregier -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
