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https://issues.apache.org/jira/browse/HBASE-20634?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16488715#comment-16488715
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Duo Zhang commented on HBASE-20634:
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Oh, MoveRegionProcedure is not RITProcedure, so it will not be cleared by
handleRIT, but it will hold the region lock, and will schedule an unassign
procedure and an assign procedure. So it means that for now, if a
MoveRegionProcedure is executed along with a ServerCrashProcedure, it will be
very likely to hang...
> Reopen region while server crash can cause the procedure to be stuck
> --------------------------------------------------------------------
>
> Key: HBASE-20634
> URL: https://issues.apache.org/jira/browse/HBASE-20634
> Project: HBase
> Issue Type: Bug
> Reporter: Duo Zhang
> Priority: Critical
> Fix For: 3.0.0, 2.1.0, 2.0.1
>
>
> Found this when implementing HBASE-20424, where we will transit the peer sync
> replication state while there is server crash.
> The problem is that, in ServerCrashAssign, we do not have the region lock, so
> it is possible that after we call handleRIT to clear the existing
> assign/unassign procedures related to this rs, and before we schedule the
> assign procedures, it is possible that that we schedule a unassign procedure
> for a region on the crashed rs. This procedure will not receive the
> ServerCrashException, instead, in addToRemoteDispatcher, it will find that it
> can not dispatch the remote call and then a FailedRemoteDispatchException
> will be raised. But we do not treat this exception the same with
> ServerCrashException, instead, we will try to expire the rs. Obviously the rs
> has already been marked as expired, so this is almost a no-op. Then the
> procedure will be stuck there for ever.
> A possible way to fix it is to treat FailedRemoteDispatchException the same
> with ServerCrashException, as it will be created in addToRemoteDispatcher
> only, and the only reason we can not dispatch a remote call is that the rs
> has already been dead. The nodeMap is a ConcurrentMap so I think we could use
> it as a guard.
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