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https://issues.apache.org/jira/browse/HBASE-13480?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14702525#comment-14702525
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Jingcheng Du commented on HBASE-13480:
--------------------------------------

Thanks guys for comments.
bq. If this is for patch version we should not break the API. Let's add a 
version of createShortCircuitHConnection with the old signature
I will add the old method back in the next patch. Since the ConnectionAdapter 
is not recommended, do we need to add deprecation for it?

bq. I would like to see tests around the changes to ensure we don't get into 
this situation again though
I will add unit tests in the next patch.

> ShortCircuitConnection doesn't short-circuit all calls as expected
> ------------------------------------------------------------------
>
>                 Key: HBASE-13480
>                 URL: https://issues.apache.org/jira/browse/HBASE-13480
>             Project: HBase
>          Issue Type: Bug
>          Components: Client
>    Affects Versions: 1.0.0, 2.0.0, 1.1.0
>            Reporter: Josh Elser
>            Assignee: Jingcheng Du
>             Fix For: 2.0.0, 1.3.0, 1.2.1, 1.0.3, 1.1.3
>
>         Attachments: HBASE-13480.patch
>
>
> Noticed the following situation in debugging unexpected unit tests failures 
> in HBASE-13351.
> {{ConnectionUtils#createShortCircuitHConnection(Connection, ServerName, 
> AdminService.BlockingInterface, ClientService.BlockingInterface)}} is 
> intended to avoid the extra RPC by calling the server's instantiation of the 
> protobuf rpc stub directly for the AdminService and ClientService.
> The problem is that this is insufficient to actually avoid extra "remote" 
> RPCs as all other calls to the Connection are routed to a "real" Connection 
> instance. As such, any object created by the "real" Connection (such as an 
> HTable) will use the real Connection, not the SSC.
> The end result is that 
> {{MasterRpcService#reportRegionStateTransition(RpcController, 
> ReportRegionStateTransitionRequest)}} will make additional "remote" RPCs over 
> what it thinks is an SSC through a {{Get}} on {{HTable}} which was 
> constructed using the SSC, but the {{Get}} itself will use the underlying 
> real Connection instead of the SSC. With insufficiently sized thread pools, 
> this has been observed to result in RPC deadlock in the HMaster where an RPC 
> attempts to make another RPC but there are no more threads available to 
> service the second RPC so the first RPC blocks indefinitely.



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