[jira] [Commented] (IGNITE-11460) MVCC: Possible race on coordinator changing on client reconnection.

[Andrew Mashenkov (JIRA)]

    [ 
https://issues.apache.org/jira/browse/IGNITE-11460?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16789680#comment-16789680
 ] 

Andrew Mashenkov commented on IGNITE-11460:
-------------------------------------------

[~NSAmelchev],

Looks like discovery guarantees that no disco events will be occurs between 
client node got ClientNodeDisconnected and Local join (after which 
ClientReconnected will be generated).

It is not clear how this race can be reproduced as all disco events should be 
serialized and coordinator can't be changed with late exchange processing in 
onExchangeDone.

> MVCC: Possible race on coordinator changing on client reconnection.
> -------------------------------------------------------------------
>
>                 Key: IGNITE-11460
>                 URL: https://issues.apache.org/jira/browse/IGNITE-11460
>             Project: Ignite
>          Issue Type: Bug
>            Reporter: Amelchev Nikita
>            Assignee: Amelchev Nikita
>            Priority: Major
>              Labels: MakeTeamcityGreenAgain
>             Fix For: 2.8
>
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> I found that the wrong coordinator can be set in case of client reconnect:
> {noformat}
> assert newCrd.topologyVersion().compareTo(curCrd.topologyVersion()) > 0;
> java.lang.AssertionError
>     at 
> org.apache.ignite.internal.processors.cache.mvcc.MvccProcessorImpl.onCoordinatorChanged(MvccProcessorImpl.java:541)
>     at 
> org.apache.ignite.internal.processors.cache.mvcc.MvccProcessorImpl.onLocalJoin(MvccProcessorImpl.java:416)
>     at 
> org.apache.ignite.internal.managers.discovery.GridDiscoveryManager$4.onDiscovery0(GridDiscoveryManager.java:851)
>     at 
> org.apache.ignite.internal.managers.discovery.GridDiscoveryManager$4.lambda$onDiscovery$0(GridDiscoveryManager.java:601)
>     at 
> org.apache.ignite.internal.managers.discovery.GridDiscoveryManager$DiscoveryMessageNotifierWorker.body0(GridDiscoveryManager.java:2681)
>     at 
> org.apache.ignite.internal.managers.discovery.GridDiscoveryManager$DiscoveryMessageNotifierWorker.body(GridDiscoveryManager.java:2719)
>     at 
> org.apache.ignite.internal.util.worker.GridWorker.run(GridWorker.java:120)
>     at java.lang.Thread.run(Thread.java:748)
> {noformat}
> I have attached reproducer in PR.
> The main reason is that coordinator can be changed from discovery event 
> thread when the client already disconnect (disconnection processed in 
> notifier thread and change coordinator on onDisconnected method).
> Coordinator can be changed in cases:
> 1. notifier disco thread: onDisconnected method
> 2. event disco thread: onDiscovery listener.
> and events can be processed with some delay and override coordinator that set 
> in notifier thread. 



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