[jira] [Created] (RATIS-203) RaftClient request may wait indefinitely for a reply

["Lokesh Jain (JIRA)" <ji...@apache.org>]

Lokesh Jain created RATIS-203:
---------------------------------

             Summary: RaftClient request may wait indefinitely for a reply
                 Key: RATIS-203
                 URL: https://issues.apache.org/jira/browse/RATIS-203
             Project: Ratis
          Issue Type: Bug
            Reporter: Lokesh Jain
            Assignee: Lokesh Jain


There are two scenarios which can lead to such a situation.
 # Raft leader accepts an entry and puts it in its retry cache. But it fails or changes before it can append the entries to its follower. In such a case the entry would remain in its retry cache. If this leader is chosen again by the ring, any subsequent request by the raft client would wait indefinitely for the future in retry cache entry to complete.
 # The leader receives the request but dies before replying to it.

Below are the log entries corresponding to first scenario.
{code:java}
2018-01-25 16:28:55,479 DEBUG impl.RaftServerImpl (LeaderState.java:addPendingRequest(239)) - s2: addPendingRequest at index=3255, request=RaftClientRequest(client-C496AD50C41A->s2) in group-8A72B1078A40, cid=3554, seq=293 RW, 322d323933
2018-01-25 16:28:57,457 DEBUG impl.RaftServerImpl (RaftServerImpl.java:submitClientRequestAsync(476)) - s2: receive client request(RaftClientRequest(client-C496AD50C41A->s2) in group-8A72B1078A40, cid=3554, seq=293 RW, 322d323933) future client-C496AD50C41A:3554:pending passedjava.util.concurrent.CompletableFuture@404d76c7[Not completed]
{code}



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)