[jboss-jira] [JBoss JIRA] Commented: (JGRP-659) Merge and UNICAST sequencing problem
[ http://jira.jboss.com/jira/browse/JGRP-659?page=comments#action_12404536 ]
Troy Schulz commented on JGRP-659:
----------------------------------
As for resolution of the problem without FLUSH, I would just like to
throw out an idea:
Since the Receiver and Sender windows are directly related to MergeView
boundaries, seems like passing the 'version' of the window along with
the message would help the receiver identify if it needs to add the
message to a new version of the window, rather than add it to the
existing window. It would continue to use the old 'version' of the
windows until it processes the MergeView. Then when it receives the
MergeView it would clean out the old version of the window and then
process the messages associated with the new window 'version'. It may
also be a good idea to pass the last id of the previous 'version' of the
window so that before the old window gets cleaned up, all of its
messages are properly processed before moving on to the new version of
the windows.
Merge and UNICAST sequencing problem
------------------------------------
Key: JGRP-659
URL: http://jira.jboss.com/jira/browse/JGRP-659
Project: JGroups
Issue Type: Bug
Affects Versions: 2.6, 2.4, 2.5
Reporter: Vladimir Blagojevic
Assigned To: Bela Ban
Fix For: 2.7
Attachments: ConcurrentMemberTest.java
The problem is related to trashing of connection table in UNICAST during merge. Consider
following scenario:
There are 4 nodes in a cluster A,B,C, and D. After network split we have two islands A,B
and C,D. When the network healing starts eventually MergeView gets installed in both
islands. MergeView installation causes trashing of UNICAST connection table [1].
However if we have a scenario where MergeView gets installed in A,B island at time T and
it gets installed in island C,D at time T+N msec and a node from island A,B sends a
unicast message in this N msec time window then we'll run into problems with unicast
sequencing at C and D. Why? Because next message coming from island A,B into C,D will be
will with sequence number > 1 and sequencing in UNICAST of C,D after connection
trashing (from merge) expects starting sequence of 1. This causes UNICAST in C and/or D to
wait forever for missing messages. Final outcome is thus that no more unicast message
coming from A and/or B will ever be delivered at C and/or D!
[1]http://jira.jboss.com/jira/browse/JGRP-348
--
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators:
http://jira.jboss.com/jira/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira