[jboss-jira] [JBoss JIRA] Commented: (JGRP-1025) Harden FLUSH

[Bela Ban (JIRA)]

    [ https://jira.jboss.org/jira/browse/JGRP-1025?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12488103#action_12488103 ] 

Bela Ban commented on JGRP-1025:
--------------------------------

Regarding overlapping flushes:

it should be possible to handle cases like this:
A: BAC
B: BC
C: BC

Merge coordinator is B  and merge participants are B and A. When B receives the merge request, it tries to flush B and C. When A receives the merge request, it tries to flush A, B and C. However, B and C will discard the flush request from A (because A is not a member in their view) and therefore, the flush from A will fail !

SOLUTION #1: flush only disjoint partitions, e.g. B flushes {B,C} while A flushes only {A}. However, we can not be sure that we can always achieve this (disjoint partitions). So maybe an additonal / complimentary solution would be

SOLUTION #2: pass an 'owner' to a flush. Default is the flush initiator, but if owner is passed, it will be the latter. In the above case, owner could be the merge-id and is as such passed to A and B. The same owner can lock multiple times, after the first time, locking is a no-op (see above).

Solution #2 doesn't of course apply to the above case, but it will harden FLUSH anyway, for cases where we cannot prevent overlapping merges (and thus overlapping flushes)





> Harden FLUSH
> ------------
>
>                 Key: JGRP-1025
>                 URL: https://jira.jboss.org/jira/browse/JGRP-1025
>             Project: JGroups
>          Issue Type: Task
>            Reporter: Bela Ban
>            Assignee: Vladimir Blagojevic
>             Fix For: 2.9
>
>
> Make sure no FLUSH is left hanging, e.g. due to the crash of the flush leader after the START-FLUSH round.
> In other words, make analyze the code and make sure STOP-FLUSH is eventually called.

-- 
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators: https://jira.jboss.org/jira/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira