[infinispan-issues] [JBoss JIRA] Commented: (ISPN-976) TopologyAwareConsistentHash does not work when numOwners=1 and rehashing

[Mircea Markus (JIRA)]

    [ https://issues.jboss.org/browse/ISPN-976?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12611246#comment-12611246 ] 

Mircea Markus commented on ISPN-976:
------------------------------------

This is no longer a problem in 5.0 given the new rebalancing code. It still applies for 4.2.x branch.

> TopologyAwareConsistentHash does not work when numOwners=1 and rehashing 
> -------------------------------------------------------------------------
>
>                 Key: ISPN-976
>                 URL: https://issues.jboss.org/browse/ISPN-976
>             Project: Infinispan
>          Issue Type: Bug
>    Affects Versions: 4.2.1.FINAL
>            Reporter: Mircea Markus
>            Assignee: Mircea Markus
>            Priority: Critical
>             Fix For: 4.2.2.BETA1, 4.2.2.FINAL
>
>
> Specifically, the problem is with getStateProvidersOnLeave.
>  
> Assume you have nodes 1, 2, and 4.
> Now node 3 joins.
> This method will iterate over each address and will skip the joiner (node3).
> For the remaining nodes it will call getOwners
> e.g. - getOwners(node1), getOwners(node2), getOwners(node3)
> This method will always begin by adding the first node in the tailMap which is the address that is being iterated over. Since numOwners is set to 1 it skips the while loop and returns the result.
> So...
> getOwners(1) returns {node1}
> getOwners(2) returns {node2}
> getOwners(4) returns {node4}
> Now we return to getStateProvidersOnLeave
> It now checks to see if the result contains the joiner (node3). However, it can never contain the joiner.

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