some 4 letter words may fail with netcat (nc) ---------------------------------------------
Key: ZOOKEEPER-737 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-737 Project: Zookeeper Issue Type: Bug Components: server Affects Versions: 3.3.0 Reporter: Patrick Hunt Priority: Blocker Fix For: 3.3.1, 3.4.0 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$fact...@251] - Accepted socket connection from /127.0.0.1:42179 2010-04-09 21:55:36,124 - INFO [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:2181:nioserverc...@968] - Processing stat command from /127.0.0.1:42179 2010-04-09 21:55:36,125 - WARN [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:2181:nioserverc...@606] - EndOfStreamException: Unable to read additional data from client sessionid 0x0, likely client has closed socket 2010-04-09 21:55:36,125 - INFO [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:2181:nioserverc...@1286] - Closed socket connection for client /127.0.0.1:42179 (no session established for client) [ph...@gsbl90850 zookeeper-3.3.0]$ 2010-04-09 21:55:36,126 - ERROR [Thread-15:nioserverc...@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$2.run(NIOServerCnxn.java:1089) 2010-04-09 21:55:36,126 - ERROR [Thread-15:nioservercnxn$factor...@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) -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: https://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira