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stack commented on HDFS-720: ---------------------------- dfs.support.append=true in this setup. > NPE in BlockReceiver$PacketResponder.run(BlockReceiver.java:923) > ---------------------------------------------------------------- > > Key: HDFS-720 > URL: https://issues.apache.org/jira/browse/HDFS-720 > Project: Hadoop HDFS > Issue Type: Bug > Affects Versions: 0.21.0 > Environment: Current branch-0.21 of hdfs, mapreduce, and common. > Here is svn info: > URL: https://svn.apache.org/repos/asf/hadoop/hdfs/branches/branch-0.21 > Repository Root: https://svn.apache.org/repos/asf > Repository UUID: 13f79535-47bb-0310-9956-ffa450edef68 > Revision: 827883 > Node Kind: directory > Schedule: normal > Last Changed Author: szetszwo > Last Changed Rev: 826906 > Last Changed Date: 2009-10-20 00:16:25 +0000 (Tue, 20 Oct 2009) > Reporter: stack > > Running some loadings on hdfs I had one of these on the DN XX.XX.XX.139:51010: > {code} > 2009-10-21 04:57:02,755 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: > Receiving block blk_6345892463926159834_1029 src: /XX,XX,XX.140:37890 dest: > /XX.XX.XX.139:51010 > 2009-10-21 04:57:02,829 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: > PacketResponder blk_6345892463926159834_1029 1 Exception > java.lang.NullPointerException > at > org.apache.hadoop.hdfs.server.datanode.BlockReceiver$PacketResponder.run(BlockReceiver.java:923) > at java.lang.Thread.run(Thread.java:619) > {code} > On XX,XX,XX.140 side, it looks like this: > {code} > 10-21 04:57:01,866 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: > Receiving block blk_6345892463926159834_1029 src: /XX.XX.XX.140:37385 dest: > /XX.XX.XX140:51010 > 2009-10-21 04:57:02,836 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: > PacketResponder 2 for block blk_6345892463926159834_1029 terminating > 2009-10-21 04:57:02,885 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: > DatanodeRegistration(XX.XX.XX.140:51010, > storageID=DS-1292310101-208.76.44.140-51010-1256100924816, infoPort=51075, > ipcPort=51020):Exception writing block blk_6345892463926159834_1029 to mirror > XX.XX.XX.139:51010 > java.io.IOException: Connection reset by peer > at sun.nio.ch.FileDispatcher.write0(Native Method) > at sun.nio.ch.SocketDispatcher.write(SocketDispatcher.java:29) > at sun.nio.ch.IOUtil.writeFromNativeBuffer(IOUtil.java:104) > at sun.nio.ch.IOUtil.write(IOUtil.java:75) > at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:334) > at > org.apache.hadoop.net.SocketOutputStream$Writer.performIO(SocketOutputStream.java:55) > at > org.apache.hadoop.net.SocketIOWithTimeout.doIO(SocketIOWithTimeout.java:142) > at > org.apache.hadoop.net.SocketOutputStream.write(SocketOutputStream.java:146) > at > org.apache.hadoop.net.SocketOutputStream.write(SocketOutputStream.java:107) > at java.io.BufferedOutputStream.write(BufferedOutputStream.java:105) > at java.io.DataOutputStream.write(DataOutputStream.java:90) > at > org.apache.hadoop.hdfs.server.datanode.BlockReceiver.receivePacket(BlockReceiver.java:466) > at > org.apache.hadoop.hdfs.server.datanode.BlockReceiver.receivePacket(BlockReceiver.java:434) > at > org.apache.hadoop.hdfs.server.datanode.BlockReceiver.receiveBlock(BlockReceiver.java:573) > at > org.apache.hadoop.hdfs.server.datanode.DataXceiver.opWriteBlock(DataXceiver.java:352) > at > org.apache.hadoop.hdfs.protocol.DataTransferProtocol$Receiver.opWriteBlock(DataTransferProtocol.java:382) > at > org.apache.hadoop.hdfs.protocol.DataTransferProtocol$Receiver.processOp(DataTransferProtocol.java:323) > at > org.apache.hadoop.hdfs.server.datanode.DataXceiver.run(DataXceiver.java:111) > at java.lang.Thread.run(Thread.java:619) > {code} > Here is the bit of code inside the run method: > {code} > 922 pkt = ackQueue.getFirst(); > 923 expected = pkt.seqno; > {code} > So 'pkt' is null? But LinkedList API says that it throws > NoSuchElementException if list is empty so you'd think we wouldn't get a NPE > here. What am I missing? -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.