QuorumCnxManager blocks forever -------------------------------- Key: ZOOKEEPER-914 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-914 Project: Zookeeper Issue Type: Bug Reporter: Vishal K Assignee: Vishal K Priority: Blocker
This was a disaster. While testing our application we ran into a scenario where a rebooted follower could not join the cluster. Further debugging showed that the follower could not join because the QuorumCnxManager on the leader was blocked for indefinite amount of time in receiveConnect() "Thread-3" prio=10 tid=0x00007fa920005800 nid=0x11bb runnable [0x00007fa9275ed000] java.lang.Thread.State: RUNNABLE at sun.nio.ch.FileDispatcher.read0(Native Method) at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:21) at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:233) at sun.nio.ch.IOUtil.read(IOUtil.java:206) at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:236) - locked <0x00007fa93315f988> (a java.lang.Object) at org.apache.zookeeper.server.quorum.QuorumCnxManager.receiveConnection(QuorumCnxManager.java:210) at org.apache.zookeeper.server.quorum.QuorumCnxManager$Listener.run(QuorumCnxManager.java:501) I had pointed out this bug along with several other problems in QuorumCnxManager earlier in https://issues.apache.org/jira/browse/ZOOKEEPER-900 and https://issues.apache.org/jira/browse/ZOOKEEPER-822. I forgot to patch this one as a part of ZOOKEEPER-822. I am working on a fix and a patch will be out soon. The problem is that QuorumCnxManager is using SocketChannel in blocking mode. It does a read() in receiveConnection() and a write() in initiateConnection(). Sorry, but this is really bad programming. Also, points out to lack of failure tests for QuorumCnxManager. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.