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From "Josh Elser (JIRA)" <j...@apache.org>
Subject [jira] [Created] (HBASE-13480) ShortCircuitConnection doesn't short-circuit all calls as expected
Date Wed, 15 Apr 2015 20:02:00 GMT
Josh Elser created HBASE-13480:
----------------------------------

             Summary: 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: Josh Elser
             Fix For: 2.0.0, 1.1.0, 1.0.2


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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