I think this service will be very useful for clustered durable queues and topics. Keep it up.
> -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Sacha > Labourey > Sent: Tuesday, August 05, 2003 2:21 AM > To: [EMAIL PROTECTED] > Subject: RE: [JBoss-dev] > DistributedReplicantManager.isMasterReplica(String) false positives? > > > Hello Bela, > > Yes, but Scott found two interesting things: > - it seems that even if two nodes share the same view, the name of the > members of the view may appear different (one has the name, the > other the IP > address) > - there is an unstable condition somewhere that make the > singleton service > flip-flap while it shouldn't be necessary (+ race condition but that's at > another level) > > I will most probably play with the additional code you had added at the > begginig of the year to add another information to the IpAddress, but for > this will have to change TCP as well (you only changed UDP) so that this > additional information is always taken in account when generating new > IpAddress at the TCP JG protocol layer. > > Cheers, > > > Sacha > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On > > Behalf Of Bela Ban > > Sent: lundi, 4. août 2003 23:55 > > To: [EMAIL PROTECTED] > > Subject: Re: [JBoss-dev] > > DistributedReplicantManager.isMasterReplica(String) false positives? > > > > > > The entire logic to determine when to become singleton is > > handled in the > > view callback. Since this can potentially be length, and also uses > > remote group calls, I suggest to run this in a separate > > thread, so you > > won't run into a deadlock. By default, HA Clustering does *not* use > > deadlock detection. > > > > > > Scott M Stark wrote: > > > > > There is a race condition i the > > > DistributedReplicantManager.isMasterReplica(String) that > > shows up when > > > this method is called from within a notifyKeyListeners as shown by > > > this stack trace: > > > > > > Thread "main"@65 status: RUNNING > > > - isMasterReplica():437, > > > org.jboss.ha.framework.server.DistributedReplicantManagerImpl > > > - isDRMMasterReplica():234, org.jboss.ha.jmx.HAServiceMBeanSupport > > > - partitionTopologyChanged():103, > > > org.jboss.ha.singleton.HASingletonSupport > > > - replicantsChanged():197, org.jboss.ha.jmx.HAServiceMBeanSupport$1 > > > - notifyKeyListeners():675, > > > org.jboss.ha.framework.server.DistributedReplicantManagerImpl > > > - add():326, > > > org.jboss.ha.framework.server.DistributedReplicantManagerImpl > > > - registerDRMListener():204, org.jboss.ha.jmx.HAServiceMBeanSupport > > > - startService():144, org.jboss.ha.jmx.HAServiceMBeanSupport > > > > > > This is due the the choice to return true when the key in > > question is > > > in the > > > localReplicants table, but not the replicants table: > > > > > > public boolean isMasterReplica (String key) > > > { > > > if (!localReplicants.containsKey (key)) > > > return false; > > > > > > Vector allNodes = this.partition.getCurrentView (); > > > HashMap repForKey = (HashMap)replicants.get(key); > > > if (repForKey==null) > > > return true; ???? > > > > > > This seems to be an ambiguous condition as this condition > > exists for a > > > node that calls add and when the state has not synched or > > has failed > > > to synch. Another problem I'm seeing at least in the context of the > > > singleton service is that the notion of the master node is > > unstable. > > > Here is the output from one of 3 nodes running the > > singleton service > > > starting with the addition of the final node shown as view 2. > > > > > > 15:35:44,637 INFO [Server] JBoss (MX MicroKernel) > > [3.2.2RC3 (build: > > > CVSTag=Branch_3_2 date=200307312219)] Started in 5s:948ms > > > 15:36:27,719 INFO [DefaultPartition] New cluster view: 2 > > > ([lamia:32947, 172.17.66.54:2821, ironmaiden:51770] delta: 1) > > > 15:36:27,749 INFO [DefaultPartition:ReplicantManager] Dead > > members: 0 > > > 15:37:13,555 INFO [DefaultPartition] New cluster view (id: > > 3, delta: > > > -1) : [172.17.66.54:2821, ironmaiden:51770] > > > 15:37:13,575 INFO [DefaultPartition:ReplicantManager] Dead > > members: 1 > > > 15:38:13,321 INFO [HASingletonMBeanExample] Notified to start as > > > singleton > > > 15:38:13,321 INFO [DefaultPartition] New cluster view (id: > > 4, delta: > > > 1) : [172.17.66.54:2821, ironmaiden:51770, lamia:32949] > > > 15:38:13,331 INFO [DefaultPartition:ReplicantManager] Dead > > members: 0 > > > 15:38:13,361 INFO [HASingletonMBeanExample] Notified to stop as > > > singleton > > > 15:39:13,447 INFO [HASingletonMBeanExample] Notified to start as > > > singleton > > > 15:39:13,457 INFO [HASingletonMBeanExample] Notified to stop as > > > singleton > > > > > > With view 3 the orginal node and singleton is killed and > > the node for > > > which the console output corresponds(172.17.66.54) is > > selected as the > > > singleton. When the third node is started again there is some > > > thrashing due to the existing 2 nodes both selecting > > themselves as the > > > singleton and telling the other to stop and it appears that > > there is > > > no singleton choosen. The problem seems to be inconsistent > > matching > > > of member names. Once only knows it IP while the other node > > knows the > > > hostnames. Here is the console view of the second node showing the > > > hostnames and its thrashing: > > > > > > 15:25:21,023 INFO [Server] JBoss (MX MicroKernel) > > [3.2.2RC3 (build: > > > CVSTag=Branch_3_2 date=200307312219)] Started in 13s:597ms > > > 15:26:05,562 INFO [DefaultPartition] New cluster view: 3 > > > ([succubus:2821, ironmaiden:51770] delta: -1) > > > 15:26:05,573 INFO [DefaultPartition:ReplicantManager] Dead > > members: 1 > > > 15:27:05,506 INFO [HASingletonMBeanExample] Notified to start as > > > singleton > > > 15:27:05,509 INFO [DefaultPartition] New cluster view: 4 > > > ([succubus:2821, ironmaiden:51770, lamia:32949] delta: 1) > > > 15:27:05,513 INFO [DefaultPartition:ReplicantManager] Dead > > members: 0 > > > 15:27:05,531 INFO [HASingletonMBeanExample] Notified to stop as > > > singleton > > > 15:28:05,520 INFO [HASingletonMBeanExample] Notified to start as > > > singleton > > > 15:28:05,526 INFO [HASingletonMBeanExample] Notified to stop as > > > singleton > > > > > > Its not clear that the > > DistributedReplicantManager.isMasterReplica was > > > designed to be used for the selection of a singleton node, > > but if it > > > is, the logic needs to be firmed up. If not, the singleton service > > > needs to be built on something else. > > > > > > > -- > > Bela Ban > > http://www.javagroups.com > > Cell: (408) 316-4459 > > > > > > > > > > ------------------------------------------------------- > > This SF.Net email sponsored by: Free pre-built ASP.NET sites including > > Data Reports, E-commerce, Portals, and Forums are available now. > > Download today and enter to win an XBOX or Visual Studio .NET. > > http://aspnet.click-url.com/go/psa00100003ave/direct;at.aspnet > > _072303_01/01 > > _______________________________________________ > > JBoss-Development mailing list > > [EMAIL PROTECTED] > > https://lists.sourceforge.net/lists/listinfo/jboss-development > > > > > > > > > ------------------------------------------------------- > This SF.Net email sponsored by: Free pre-built ASP.NET sites including > Data Reports, E-commerce, Portals, and Forums are available now. > Download today and enter to win an XBOX or Visual Studio .NET. > http://aspnet.click-url.com/go/psa00100003ave/direct;at.aspnet_072 303_01/01 _______________________________________________ JBoss-Development mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/jboss-development ------------------------------------------------------- This SF.Net email sponsored by: Free pre-built ASP.NET sites including Data Reports, E-commerce, Portals, and Forums are available now. 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