[jbosscache-issues] [JBoss JIRA] Created: (JBCACHE-1530) Stale copies of gravitated data left in "xxx:DEAD trees

[Brian Stansberry (JIRA)]

Stale copies of gravitated data left in "xxx:DEAD trees
-------------------------------------------------------

                 Key: JBCACHE-1530
                 URL: https://jira.jboss.org/jira/browse/JBCACHE-1530
             Project: JBoss Cache
          Issue Type: Bug
      Security Level: Public (Everyone can see)
    Affects Versions: 3.2.0.BETA1
            Reporter: Brian Stansberry
            Assignee: Manik Surtani


There's a race that can result in a stale copy of gravitated data being left in a "/BUDDY_BACKUP/xxx:DEAD" tree:

Scenario:

1) Data is store in /B_B/xxx/foo
2) xxx is leaving group
3) Gravitate data command for /B_B/xxx/foo comes in, result is returned
4) Buddy group re-formation thread move /B_B/xxx/foo to /B_B/xxx:DEAD/1/foo
5) DataGravitationCleanupCommand comes in for /B_B/xxx/foo which results in nothing happening since the node is moved

A fix might involve some analysis of the backup fqn in the DataGravitationCleanupCommand, try to detect this condition.  Or perhaps tracking successful GravitationResult responses, trying to match against the cleanup command.

As a quick workaround I'm going to investigate an algorithm on the GravitateDataCommand sender side to not just accept the first successful result but rather to compare all positive results, giving preference to:

1) A result from the main tree
2) A result from a non :DEAD buddy backup tree
3) A result from xxx:DEAD/2
4) A result from xxx:DEAD/1

-- 
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