[jboss-jira] [JBoss JIRA] (JGRP-2092) MERGE3: merge never happens

[Neal Dillman (JIRA)]

    [ https://issues.jboss.org/browse/JGRP-2092?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13292108#comment-13292108 ] 

Neal Dillman commented on JGRP-2092:
------------------------------------

This scenario happened several times in our lab.  We no longer see the issue as it was worked around with staggering responses for all of the "bulk response" messages (ie: view change, etc).  However, I believe that this could happen again with a marge enough network and low enough bandwidth.  In other words my ounce of prevention is working out, be the pound of cure would still be the best solution.  I had created a unit test as well and hound the same results.  We also ran into partial scenarios where the consistency checker was being run by one functioning coordinator, but other, non-functioning coordinators would not respond to the merge and/or the coordinator running the checker did not think it should be merge leader.  In all cases the issue is complicated by the fact that none of the non-coordinators will trust a new coordinator that is not a member of their group.

I believe that a solution will involve the 2nd rank host (and maybe the 3rd?) running a checker to see if the coordinator's viewInfo shows the coordinator as thinking it is, in fact, a coordinator.

> MERGE3: merge never happens
> ---------------------------
>
>                 Key: JGRP-2092
>                 URL: https://issues.jboss.org/browse/JGRP-2092
>             Project: JGroups
>          Issue Type: Bug
>            Reporter: Bela Ban
>            Assignee: Bela Ban
>             Fix For: 3.6.11, 4.0
>
>         Attachments: jgroups.txt
>
>
> (Reported by Neal Dillman)
> In the case below, a merge doesn't seem to happen. Write a unit test to reprodue this.
> {noformat}
> Host A view: B, X, Y, Z, A  (where B should be coordinator)
> Host B view: C, Q, R, S, B (where C should be coordinator)
> Host C view: A, M, N, O, C (where A should be coordinator)
> {noformat}



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