[jboss-jira] [JBoss JIRA] Commented: (JBREM-956) Client side does not detect connection drop when LeasePinger is active, therefore remaining blocked.

[Ron Sigal (JIRA)]

    [ http://jira.jboss.com/jira/browse/JBREM-956?page=comments#action_12407208 ] 
            
Ron Sigal commented on JBREM-956:
---------------------------------

Hi Guy,

I believe you're thinking of the function of org.jboss.remoting.ConnectionValidator, rather than LeasePinger. 

1. The function of LeasePinger is to send pings to the server to keep a server-side org.jboss.remoting.Lease alive.  If the pings from LeasePinger fail to arrive in time, the Lease informs server side listeners of a connection problem.

2. The function of ConnectionValidator is to solicit from the server a response to a ping.  If the response does not arrive in time, the ConnectionValidator informs client side listeners of a connection problem.

So it's ConnectionValidator that suffers from the problem you're describing.  And, it turns out that this problem is already covered by JIRA issues:

  * Release 2.2.2.SP8: JBREM-947: ConnectionValidator hangs when server dies

  * Release 2.4.0.GA: JBREM-948: CLONE [JBREM-947] - ConnectionValidator hangs when server dies

If I'm missing something, please let me know.  Otherwise, I will close the issue (but still solve the problem).

Thanks.

> Client side does not detect connection drop when LeasePinger is active, therefore remaining blocked.
> ----------------------------------------------------------------------------------------------------
>
>                 Key: JBREM-956
>                 URL: http://jira.jboss.com/jira/browse/JBREM-956
>             Project: JBoss Remoting
>          Issue Type: Bug
>      Security Level: Public(Everyone can see) 
>          Components: transport
>    Affects Versions: 2.0.0.GA (Boon), 2.4.0.Beta1 (Pinto), 2.4.0.CR1 (Pinto), 2.2.0.GA (Bluto), 2.2.0.SP1, 2.2.0.SP2, 2.2.0.SP3, 2.2.0.SP4, 2.2.1.GA, 2.2.2.GA, 2.2.2.SP1, 2.2.2.GA_CP01, 2.2.2.SP2, 2.2.2.GA_CP02, 2.2.2.GA_CP03, 2.2.2.SP4, 2.2.2.SP5,  2.4.0.Beta2 (Pinto)
>         Environment: JBoss 4.2.1,  Windows XP SP2, Redhat Enterprise Linux 3.0
>            Reporter: Guy Nir
>         Assigned To: Ron Sigal
>             Fix For: 2.4.0.GA
>
>
> When a client and server resides on different machines and server suddenly disconnected from the network (i.e.: cable disconnected or host is cord-reseted/power down brutely) the client side does not recognize this situation and remains blocking.
> The main reason for this behavior is that TCP does not provide direct indication that a connection is dropped (unless a probe such as KeepAlive is activated).
> The LeasePinger class should resolve this issue, however, the invocation of sendClientPing() method remains blocking as well.
> A different shorter timeout should be placed for sendClientPing() (perhaps timeout-per-invocation approach ?).
> For example, instead of using the following implementation (taken from sendClientPing) :
>          Map clientsClone = new ConcurrentHashMap(clients);
>          Map requestClients = new ConcurrentHashMap();
>          requestClients.put(ClientHolder.CLIENT_HOLDER_KEY, clientsClone);
>          InvocationRequest ir = new InvocationRequest(invokerSessionID, null, "$PING$", requestClients, null, null);
>          invoker.invoke(ir);
> It is possible to use:
>          int clientPingLeaseTimeout = ......;
>          Map clientsClone = new ConcurrentHashMap(clients);
>          Map requestClients = new ConcurrentHashMap();
>          requestClients.put(ClientHolder.CLIENT_HOLDER_KEY, clientsClone);
>          requestClients.put(ServerInvoker.TIMEOUT, clientPingLeaseTimeout);
>          InvocationRequest ir = new InvocationRequest(invokerSessionID, null, "$PING$", requestClients, null, null);
>          invoker.invoke(ir);

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