[jboss-jira] [JBoss JIRA] Commented: (JGRP-505) UNICAST: sequence numbering after merge leads to messages never being delivered

Wed Jun 6 15:36:09 EDT 2007

    [ http://jira.jboss.com/jira/browse/JGRP-505?page=comments#action_12364420 ] 

Vladimir Blagojevic commented on JGRP-505:
------------------------------------------

Yes exactly. That was my conclusion as well: race between merge view and unicast.

> UNICAST: sequence numbering after merge leads to messages never being delivered
> -------------------------------------------------------------------------------
>
>                 Key: JGRP-505
>                 URL: http://jira.jboss.com/jira/browse/JGRP-505
>             Project: JGroups
>          Issue Type: Bug
>    Affects Versions: 2.4.1
>            Reporter: Vladimir Blagojevic
>         Assigned To: Vladimir Blagojevic
>             Fix For: 2.5
>
>
> During refactoring of TUNNEL to use TP I ran MultiplexerMergeTest very often. This test basically consists of two members A and B that are exchanging message through GossipRouter. When GossipRouter is killed members form their own subgroups that are subsequently merged once router starts again. 
> I noticed that on very rare occasions (1 in 20 test runs) one of the members (say A) stops passing up unicast messages from B above UNICAST protocol. More detailed logging and inquiry at UNICAST revealed that upon merge A stops passing up messages from B and keeps adding messages from B seq>1 into B's window but does not pass up messages further since message seq B1 is missing. After further investigation I concluded that message B1 must have been delivered to A prior to MergeView. MergeView wiped clean all windows and added next sequence B2 to appropriate window. 
> I am not sure if this is only applicable to Multiplexer setup. The issue is hard to reproduce. I will see if it is possible to make a unit test to reproduce it.

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