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https://issues.apache.org/jira/browse/HADOOP-19061?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17813444#comment-17813444
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ASF GitHub Bot commented on HADOOP-19061:
-----------------------------------------
simbadzina commented on PR #6519:
URL: https://github.com/apache/hadoop/pull/6519#issuecomment-1922606916
>The new code would remove that bad connection object and a new good one
will be created next time.
Do we log the bag connection which was cleaned up?
What happens if there is an OOM when creating the new connection? Wondering
is we can get into a live-lock.
Please do excuse the many questions, I'm not familiar with this code so this
is to help my understanding.
> Capture exception in rpcRequestSender.start() in IPC.Connection.run()
> ---------------------------------------------------------------------
>
> Key: HADOOP-19061
> URL: https://issues.apache.org/jira/browse/HADOOP-19061
> Project: Hadoop Common
> Issue Type: Bug
> Components: ipc
> Affects Versions: 3.5.0
> Reporter: Xing Lin
> Assignee: Xing Lin
> Priority: Major
> Labels: pull-request-available
>
> _rpcRequestThread.start()_ is called outside of the try-catch{} block.
> However, it can throw OOM. In such cases, we fail to start the Connection and
> Connection.rpcRequestThread threads. However, this OOM won't be captured in
> {_}Connection.setupIOStreams(){_}. Instead, that function returns and
> getConnection() will return an Connection object and we will continue with
> _connection.sendRpcRequest(call). sendRpcRequest()_ will then be hanging
> forever at its while loop, because we don't mark this connection as closed
> and we don't have the rpcRequestSender thread to poll the request from the
> queue.
> {code:java}
> IPC.Connection.run()
> @Override
> public void run() {
> // Don't start the ipc parameter sending thread until we start this
> // thread, because the shutdown logic only gets triggered if this
> // thread is started.
> rpcRequestThread.start();
> if (LOG.isDebugEnabled())
> LOG.debug(getName() + ": starting, having connections "
> + connections.size());
> try {
> while (waitForWork()) {//wait here for work - read or close connection
> receiveRpcResponse();
> }
> } catch (Throwable t) {
> // This truly is unexpected, since we catch IOException in
> receiveResponse
> // -- this is only to be really sure that we don't leave a client
> hanging
> // forever.
> LOG.warn("Unexpected error reading responses on connection " + this,
> t);
> markClosed(new IOException("Error reading responses", t));
> }{code}
> while loop in sendRpcRequest
> {code:java}
> while (!shouldCloseConnection.get()) {
> if (rpcRequestQueue.offer(Pair.of(call, buf), 1, TimeUnit.SECONDS)) {
> break;
> }
> }{code}
> OOM exception in starting the rpcRequestSender thread.
> {code:java}
> Exception in thread "IPC Client (1664093259) connection to
> nn01.grid.linkedin.com/IP-Address:portNum from kafkaetl"
> java.lang.OutOfMemoryError: unable to create new native thread
> at java.lang.Thread.start0(Native Method)
> at java.lang.Thread.start(Thread.java:717)
> at org.apache.hadoop.ipc.Client$Connection.run(Client.java:1034)
> {code}
> Multiple threads blocked by queue.offer(). and we don't found any "IPC
> Client" or "IPC Parameter Sending Thread" in thread dump.
> {code:java}
> Thread 2156123: (state = BLOCKED)
> - sun.misc.Unsafe.park(boolean, long) @bci=0 (Compiled frame; information
> may be imprecise)
> - java.util.concurrent.locks.LockSupport.parkNanos(java.lang.Object, long)
> @bci=20, line=215 (Compiled frame)
> -
> java.util.concurrent.SynchronousQueue$TransferQueue.awaitFulfill(java.util.concurrent.SynchronousQueue$TransferQueue$QNode,
> java.lang.Object, boolean, long) @bci=156, line=764 (Compiled frame)
> -
> java.util.concurrent.SynchronousQueue$TransferQueue.transfer(java.lang.Object,
> boolean, long) @bci=148, line=695 (Compiled frame)
> - java.util.concurrent.SynchronousQueue.offer(java.lang.Object, long,
> java.util.concurrent.TimeUnit) @bci=24, line=895 (Compiled frame)
> -
> org.apache.hadoop.ipc.Client$Connection.sendRpcRequest(org.apache.hadoop.ipc.Client$Call)
> @bci=88, line=1134 (Compiled frame)
> - org.apache.hadoop.ipc.Client.call(org.apache.hadoop.ipc.RPC$RpcKind,
> org.apache.hadoop.io.Writable, org.apache.hadoop.ipc.Client$ConnectionId,
> int, java.util.concurrent.atomic.AtomicBoolean,
> org.apache.hadoop.ipc.AlignmentContext) @bci=36, line=1402 (Interpreted frame)
> - org.apache.hadoop.ipc.Client.call(org.apache.hadoop.ipc.RPC$RpcKind,
> org.apache.hadoop.io.Writable, org.apache.hadoop.ipc.Client$ConnectionId,
> java.util.concurrent.atomic.AtomicBoolean,
> org.apache.hadoop.ipc.AlignmentContext) @bci=9, line=1349 (Compiled frame)
> - org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(java.lang.Object,
> java.lang.reflect.Method, java.lang.Object[]) @bci=248, line=230 (Compiled
> frame)
> - org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(java.lang.Object,
> java.lang.reflect.Method, java.lang.Object[]) @bci=4, line=118 (Compiled
> frame)
> - com.sun.proxy.$Proxy11.getBlockLocations({code}
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