[infinispan-issues] [JBoss JIRA] (ISPN-1965) Some entries not available during view change

[RH Bugzilla Integration (JIRA)]

    [ https://issues.jboss.org/browse/ISPN-1965?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12681950#comment-12681950 ] 

RH Bugzilla Integration commented on ISPN-1965:
-----------------------------------------------

Misha H. Ali <mhusnain at redhat.com> made a comment on [bug 808623|https://bugzilla.redhat.com/show_bug.cgi?id=808623]


    Technical note updated. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    Diffed Contents:
@@ -1 +1,3 @@
-When the view is changed, some entries are unavailable to some clients, despite existing in the cluster and being loaded in the data loading phase. The total number of entries (retrieved by JMX) is correct, therefore the missing entries are not lost. This error occurs for a brief period of time and then ceases.+When a number of nodes larger than the value of numOwner leave a cluster, JBoss Data Grid cannot guarantee that all key values are preserved. In a four node cluster, each partition has two nodes. As a result, each partition loses a number of nodes that equals the value of numOwner and keys that exist prior to the nodes leaving the cluster may not be preserved in both partitions.
+
+When partitions are merged into a single cluster, key values are preserved in the new cluster (assuming that no clients modified these values during the network split). If a client modified a key during the network split, the old value may be retrieved, the new value may be retrieved, and in some cases the old value may be retrieved after the old value is retrieved. This policy applies to creation and removal as well, if the missing key is equated with a null value..
                
> Some entries not available during view change
> ---------------------------------------------
>
>                 Key: ISPN-1965
>                 URL: https://issues.jboss.org/browse/ISPN-1965
>             Project: Infinispan
>          Issue Type: Bug
>    Affects Versions: 5.1.3.FINAL
>            Reporter: Michal Linhard
>            Assignee: Dan Berindei
>
> In the 4 node, dist mode, num-owners=2, elasticity test
> http://www.qa.jboss.com/~mlinhard/hyperion/run44-elas-dist/
> there is a cca 90 sec period of time where clients get null responses to GET
> requests on entries that should exist in the cache.
> first occurence:
> hyperion1139.log 05:31:01,202 286.409
> last occurence:
> hyperion1135.log 05:32:45,441 390.648
> total occurence count: (in all 19 driver nodes)
> 152241
> (this doesn't mean it happens for 152K keys, because each key is retried after
> erroneous attempt)
> data doesn't seem to be lost, because these errors cease after a while and
> number of entries returns back to normal (see cache_entries.csv)
> this happens approximately in the period between node0001 is killed and cluster
> {node0002 - node0004} is formed (and shortly after).

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