ZooKeeper
  1. ZooKeeper
  2. ZOOKEEPER-737

some 4 letter words may fail with netcat (nc)

    Details

    • Type: Bug Bug
    • Status: Closed
    • Priority: Blocker Blocker
    • Resolution: Fixed
    • Affects Version/s: 3.3.0
    • Fix Version/s: 3.3.1, 3.4.0
    • Component/s: server
    • Labels:
      None
    • Hadoop Flags:
      Reviewed

      Description

      nc closes the write channel as soon as it's sent it's information, for example "echo stat|nc localhost 2181"
      in general this is fine, however the server code will close the socket as soon as it receives notice that nc has
      closed it's write channel. if not all the 4 letter word result has been written back to the client yet, this will cause
      some or all of the result to be lost - ie the client will not see the full result. this was introduced in 3.3.0 as part
      of a change to reduce blocking of the selector by long running 4letter words.

      here's an example of the logs from the server during this

      echo -n stat | nc localhost 2181
      2010-04-09 21:55:36,124 - INFO [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:2181:NIOServerCnxn$Factory@251] - Accepted socket connection from /127.0.0.1:42179
      2010-04-09 21:55:36,124 - INFO [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:2181:NIOServerCnxn@968] - Processing stat command from /127.0.0.1:42179
      2010-04-09 21:55:36,125 - WARN [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:2181:NIOServerCnxn@606] - EndOfStreamException: Unable to read additional data from client sessionid 0x0, likely client has closed socket
      2010-04-09 21:55:36,125 - INFO [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:2181:NIOServerCnxn@1286] - Closed socket connection for client /127.0.0.1:42179 (no session established for client)
      [phunt@gsbl90850 zookeeper-3.3.0]$ 2010-04-09 21:55:36,126 - ERROR [Thread-15:NIOServerCnxn@422] - Unexpected Exception:
      java.nio.channels.CancelledKeyException
      at sun.nio.ch.SelectionKeyImpl.ensureValid(SelectionKeyImpl.java:55)
      at sun.nio.ch.SelectionKeyImpl.interestOps(SelectionKeyImpl.java:59)
      at org.apache.zookeeper.server.NIOServerCnxn.sendBuffer(NIOServerCnxn.java:395)
      at org.apache.zookeeper.server.NIOServerCnxn$SendBufferWriter.checkFlush(NIOServerCnxn.java:907)
      at org.apache.zookeeper.server.NIOServerCnxn$SendBufferWriter.flush(NIOServerCnxn.java:945)
      at java.io.BufferedWriter.flush(BufferedWriter.java:236)
      at java.io.PrintWriter.flush(PrintWriter.java:276)
      at org.apache.zookeeper.server.NIOServerCnxn$2.run(NIOServerCnxn.java:1089)
      2010-04-09 21:55:36,126 - ERROR [Thread-15:NIOServerCnxn$Factory$1@82] - Thread Thread[Thread-15,5,main] died
      java.nio.channels.CancelledKeyException
      at sun.nio.ch.SelectionKeyImpl.ensureValid(SelectionKeyImpl.java:55)
      at sun.nio.ch.SelectionKeyImpl.interestOps(SelectionKeyImpl.java:64)
      at org.apache.zookeeper.server.NIOServerCnxn$SendBufferWriter.wakeup(NIOServerCnxn.java:927)
      at org.apache.zookeeper.server.NIOServerCnxn$SendBufferWriter.checkFlush(NIOServerCnxn.java:909)
      at org.apache.zookeeper.server.NIOServerCnxn$SendBufferWriter.flush(NIOServerCnxn.java:945)
      at java.io.BufferedWriter.flush(BufferedWriter.java:236)
      at java.io.PrintWriter.flush(PrintWriter.java:276)
      at org.apache.zookeeper.server.NIOServerCnxn$2.run(NIOServerCnxn.java:1089)

      1. ZOOKEEPER-737.patch
        24 kB
        Mahadev konar
      2. ZOOKEEPER-737.patch
        8 kB
        Mahadev konar
      3. ZOOKEEPER-737.patch
        8 kB
        Mahadev konar
      4. ZOOKEEPER-737.patch
        8 kB
        Mahadev konar
      5. ZOOKEEPER-737.patch
        9 kB
        Patrick Hunt
      6. ZOOKEEPER-737.patch
        8 kB
        Mahadev konar
      7. ZOOKEEPER-737.patch
        7 kB
        Mahadev konar

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            People

            • Assignee:
              Mahadev konar
              Reporter:
              Patrick Hunt
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              Dates

              • Created:
                Updated:
                Resolved:

                Development