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https://issues.apache.org/jira/browse/IGNITE-12451?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17200262#comment-17200262
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Aleksey Plekhanov commented on IGNITE-12451:
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[~maliev], when an old thread can't lock entry, {{hasLockCollisions}} returns
{{false}} for this thread (since there isn't another older thread exists which
holds this lock) and an old thread tries to lock this entry again.
When a new thread can't lock entry, {{hasLockCollisions}} returns {{true}} for
this thread (since there is another older thread exists which holds this lock)
and a new thread release all acquired locks and retry the whole operation.
After locks have been released by a new thread - an old thread can acquire the
lock it was waited for and proceed further. So, all deadlocks will be
eventually resolved.
> Introduce deadlock detection for cache entry reentrant locks
> ------------------------------------------------------------
>
> Key: IGNITE-12451
> URL: https://issues.apache.org/jira/browse/IGNITE-12451
> Project: Ignite
> Issue Type: Improvement
> Affects Versions: 2.7.6
> Reporter: Ivan Rakov
> Assignee: Mirza Aliev
> Priority: Major
> Fix For: 2.10
>
> Time Spent: 10m
> Remaining Estimate: 0h
>
> Aside from IGNITE-12365, we still have possible threat of cache-entry-level
> deadlock in case of careless usage of JCache mass operations (putAll,
> removeAll):
> 1. If two different user threads will perform putAll on the same two keys in
> reverse order (primary node for which is the same), there's a chance that
> sys-stripe threads will be deadlocked.
> 2. Even without direct contract violation from user side, HashMap can be
> passed as argument for putAll. Even if user threads have called mass
> operations with two keys in the same order, HashMap iteration order is not
> strictly defined, which may cause the same deadlock.
> Local deadlock detection should mitigate this issue. We can create a wrapper
> for ReentrantLock with logic that performs cycle detection in wait-for graph
> in case we are waiting for lock acquisition for too long. Exception will be
> thrown from one of the threads in such case, failing user operation, but
> letting the system make progress.
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