[jira] [Updated] (IGNITE-5613) AtomicSequence usage inside transactions may cause deadlock

["Alexey Goncharuk (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IGNITE-5613?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Alexey Goncharuk updated IGNITE-5613:
-------------------------------------
    Labels: important  (was: )

> AtomicSequence usage inside transactions may cause deadlock
> -----------------------------------------------------------
>
>                 Key: IGNITE-5613
>                 URL: https://issues.apache.org/jira/browse/IGNITE-5613
>             Project: Ignite
>          Issue Type: Bug
>          Components: cache
>    Affects Versions: 1.5.0.final
>            Reporter: Alexey Goncharuk
>              Labels: important
>             Fix For: 2.1
>
>
> Consider the following update scenario:
> {code}
> Thread 1:
> Transaction tx = txStart() {
>     get(key); // Acquires lock;
>     seq.incrementAndGet();
> }
> Thread 2:
> seq.incrementAndGet();
> {code}
> Let's now assume that:
>  * Sequence is exhausted and needs a non-local update
>  * Thread 1 acquired lock on topology version N
>  * Topology version changes
>  * Thread 2 now calls incrementAndGet(), updates the sequence local guard and starts transaction which waits for topology version N+1 to become available
>  * Thread 1 attemts to incrementAndGet().
> Since guard is already changed, it waits for the concurrent update to complete



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