Hua xu created HADOOP-9684:
------------------------------
Summary: the initialization or missed may be for
org.apache.ipc.Client$Connection
Key: HADOOP-9684
URL: https://issues.apache.org/jira/browse/HADOOP-9684
Project: Hadoop Common
Issue Type: Bug
Components: ipc
Affects Versions: 0.21.0, 1.0.3
Reporter: Hua xu
Today, we see that a TaskTracer has keeped throwing the same exception in our
production environment.it is that:
2013-07-01 18:41:40,023 INFO org.apache.hadoop.mapred.TaskTracker: addFreeSlot
: current free slots : 7
2013-07-01 18:41:43,026 INFO org.apache.hadoop.mapred.TaskTracker:
LaunchTaskAction (registerTask): attempt_201208241212_27521_m_000002_3 task's
state:UNASSIGNED
2013-07-01 18:41:43,026 INFO org.apache.hadoop.mapred.TaskTracker: Trying to
launch : attempt_201208241212_27521_m_000002_3 which needs 1 slots
2013-07-01 18:41:43,026 INFO org.apache.hadoop.mapred.TaskTracker: In
TaskLauncher, current free slots : 7 and trying to launch
attempt_201208241212_27521_m_000002_3 which needs 1 slots
2013-07-01 18:41:43,026 INFO
org.apache.hadoop.mapreduce.server.tasktracker.Localizer: User-directories for
the user sds are already initialized on this TT. Not doing anything.
2013-07-01 18:41:43,029 WARN org.apache.hadoop.mapred.TaskTracker: Error
initializing attempt_201208241212_27521_m_000002_3:
java.lang.NullPointerException
2013-07-01 18:41:43,029 ERROR org.apache.hadoop.mapred.TaskStatus: Trying to
set finish time for task attempt_201208241212_27521_m_000002_3 when no start
time is set, stackTrace is : java.lang.Exception
at
org.apache.hadoop.mapred.TaskStatus.setFinishTime(TaskStatus.java:195)
at
org.apache.hadoop.mapred.MapTaskStatus.setFinishTime(MapTaskStatus.java:51)
at
org.apache.hadoop.mapred.TaskTracker$TaskInProgress.kill(TaskTracker.java:2937)
at
org.apache.hadoop.mapred.TaskTracker.startNewTask(TaskTracker.java:2255)
at
org.apache.hadoop.mapred.TaskTracker$TaskLauncher.run(TaskTracker.java:2212)
Then, we view the log files of the TaskTracker,and find that the TaskTracker
throwed Several OutOfMemoryError: Java heap space about ten days ago. after
that, the TaskTracker has still throws the exception:
2013-06-22 12:39:42,296 INFO org.apache.hadoop.mapred.TaskTracker:
LaunchTaskAction (registerTask): attempt_201208241212_26088_m_000043_1 task's
state:UNASSIGNED
2013-06-22 12:39:42,296 INFO org.apache.hadoop.mapred.TaskTracker: Trying to
launch : attempt_201208241212_26088_m_000043_1 which needs 1 slots
2013-06-22 12:39:42,296 INFO org.apache.hadoop.mapred.TaskTracker: In
TaskLauncher, current free slots : 7 and trying to launch
attempt_201208241212_26088_m_000043_1 which needs 1 slots
2013-06-22 12:39:42,296 INFO
org.apache.hadoop.mapreduce.server.tasktracker.Localizer: Initializing user sds
on this TT.
2013-06-22 12:39:42,300 WARN org.apache.hadoop.mapred.TaskTracker: Error
initializing attempt_201208241212_26088_m_000043_1:
java.lang.NullPointerException
at org.apache.hadoop.ipc.Client$Connection.sendParam(Client.java:630)
at org.apache.hadoop.ipc.Client.call(Client.java:886)
at
org.apache.hadoop.ipc.WritableRpcEngine$Invoker.invoke(WritableRpcEngine.java:198)
at $Proxy5.getFileInfo(Unknown Source)
at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at
org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:82)
at
org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:59)
at $Proxy5.getFileInfo(Unknown Source)
at org.apache.hadoop.hdfs.DFSClient.getFileInfo(DFSClient.java:850)
at
org.apache.hadoop.hdfs.DistributedFileSystem.getFileStatus(DistributedFileSystem.java:620)
at
org.apache.hadoop.mapred.TaskTracker.localizeJobTokenFile(TaskTracker.java:3984)
at
org.apache.hadoop.mapred.TaskTracker.localizeJobFiles(TaskTracker.java:1036)
at
org.apache.hadoop.mapred.TaskTracker.localizeJob(TaskTracker.java:977)
at
org.apache.hadoop.mapred.TaskTracker.startNewTask(TaskTracker.java:2247)
at
org.apache.hadoop.mapred.TaskTracker$TaskLauncher.run(TaskTracker.java:2212)
2013-06-22 12:39:42,300 ERROR org.apache.hadoop.mapred.TaskStatus: Trying to
set finish time for task attempt_201208241212_26088_m_000043_1 when no start
time is set, stackTrace is : java.lang.Exception
at
org.apache.hadoop.mapred.TaskStatus.setFinishTime(TaskStatus.java:195)
at
org.apache.hadoop.mapred.MapTaskStatus.setFinishTime(MapTaskStatus.java:51)
at
org.apache.hadoop.mapred.TaskTracker$TaskInProgress.kill(TaskTracker.java:2937)
at
org.apache.hadoop.mapred.TaskTracker.startNewTask(TaskTracker.java:2255)
at
org.apache.hadoop.mapred.TaskTracker$TaskLauncher.run(TaskTracker.java:2212)
Since then, the TaskTracker has not completed any task.we can find the
property of Connection -out is null from the above exeption,and it is caused by
the failure of method setupIOstream() in the class
org.apache.ipc.Client$Connection.anyway, the instance of Connection is not null
and cached by the org.apache.ipc.Client.We guess that it throwed a
OutOfMemoryError when a thread called the setupIOstream() because of RPC, so
that some properties of the Connection are null, and throw NullPointerException
when the Connection are accessed by other threads,which is fron the cache.It
must be correct to make sure that the instance of Connection could only be
cached after initialized successfully. We fixed the Method getConnection() to
guarantee the semantic:
private Connection getConnection(InetSocketAddress addr,
Class<?> protocol,
UserGroupInformation ticket,
Call call)
throws IOException, InterruptedException {
if (!running.get()) {
// the client is stopped
throw new IOException("The client is stopped");
}
Connection connection;
/* we could avoid this allocation for each RPC by having a
* connectionsId object and with set() method. We need to manage the
* refs for keys in HashMap properly. For now its ok.
*/
ConnectionId remoteId = new ConnectionId(addr, protocol, ticket);
do {
synchronized (connections) {
connection = connections.get(remoteId);
if (connection == null) {
connection = new Connection(remoteId);
+ connection.setupIOstreams();
connections.put(remoteId, connection);
}
}
} while (!connection.addCall(call));
//we don't invoke the method below inside "synchronized (connections)"
//block above. The reason for that is if the server happens to be slow,
//it will take longer to establish a connection and that will slow the
//entire system down.
- connection.setupIOstreams();
return connection;
}
On the other hand, we also simulate this scenario.Firstly, one thread create
the Connection instance and throw OutOfMemoryError when it call
connection.setupIOstreams().after that, the other thread start call RPC through
by the instance and it keeps throwing the same exceptions
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