[jboss-jira] [JBoss JIRA] Created: (JGRP-1179) Incoming PingRsp is ignored despite being sent by a Coordinator.

[Renaud Devarieux (JIRA)]

Incoming PingRsp is ignored despite being sent by a Coordinator.
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                 Key: JGRP-1179
                 URL: https://jira.jboss.org/jira/browse/JGRP-1179
             Project: JGroups
          Issue Type: Bug
    Affects Versions: 2.6.14, 2.6.9
         Environment: Linux Red Hat Enterprise 5.0 kernel 2.6.18-8.el5 java 1.6.0_18
            Reporter: Renaud Devarieux
            Assignee: Bela Ban


I launch successively (nearly simultaneously) 5 nodes A B C D E using the same protocol stack and one channel to communicate between themselves.

UDP(mcast_addr=231.8.8.8;mcast_port=45578):PING(num_initial_members=4):MERGE2:FD:VERIFY_SUSPECT:pbcast.NAKACK:pbcast.STABLE:FRAG2:pbcast.GMS(shun=true):pbcast.FLUSH

Often as not, it depends on the speed/rythm between each node launch, I get 2 views, ie {D} and  {A B C E}.

Merge occurs later but when it does it's a bit late for my application and I don't think I should have to handle one save in case of a real electric/network failure.

I noticed that on D I was timing out (3000ms) on during the discovery process despite having received the 4 GET_MBRS_RSP of the other nodes. Then D would decide there was no coordinator outside and become coordinator itself.

What seems to happen is D sends two GET_MBRS_REQ and A replies to both, but at the time of the first reply, A is not yet coordinator and when D receives the second response, A became coordinator but D ignores the response and doesn"t add it to its list of Responses.

I have written a workaround in Discovery.Responses method addResponse, it seems to work for my case but I am afraid it would break something else I am not aware of.

        public void addResponse(PingRsp rsp) {
            if(rsp == null)
                return;
            promise.getLock().lock();
            try {
                //Workaround 29/03/2010
                int index = ping_rsps.indexOf(rsp);

                // equivalent to does not contain.
                if (index == -1) {
                    ping_rsps.add(rsp);
                    promise.getCond().signalAll();
                } else if (rsp.isCoord()) {
                    PingRsp pr = ping_rsps.get(index);
                  
                    //Check if the already existing element is not server
                    if (!pr.isCoord()) {
                        ping_rsps.set(index, rsp);
                        promise.getCond().signalAll();
                    }
                }

                /*if(!ping_rsps.contains(rsp)) {
                    ping_rsps.add(rsp);
                        promise.getCond().signalAll();
                }*/ // Old JGroups code
            }
            finally {
                promise.getLock().unlock();
            }
        }

Regards
Renaud





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