reduce speculation on but ParseOutputFormat doesn't name output files correctly? --------------------------------------------------------------------------------
Key: NUTCH-1315 URL: https://issues.apache.org/jira/browse/NUTCH-1315 Project: Nutch Issue Type: Bug Components: parser Affects Versions: 1.4 Environment: ubuntu 64bit, hadoop 1.0.1, 3 Node Cluster, segment size 1.5M urls Reporter: Rafael >From time to time the Reducer log contains the following and one tasktracker >gets blacklisted. org.apache.hadoop.ipc.RemoteException: org.apache.hadoop.hdfs.protocol.AlreadyBeingCreatedException: failed to create file /user/test/crawl/segments/20120316065507/parse_text/part-00001/data for DFSClient_attempt_201203151054_0028_r_000001_1 on client xx.x.xx.xx.10, because this file is already being created by DFSClient_attempt_201203151054_0028_r_000001_0 on xx.xx.xx.9 at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.recoverLeaseInternal(FSNamesystem.java:1404) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFileInternal(FSNamesystem.java:1244) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFile(FSNamesystem.java:1186) at org.apache.hadoop.hdfs.server.namenode.NameNode.create(NameNode.java:628) at sun.reflect.GeneratedMethodAccessor8.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:563) at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1388) at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1384) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:396) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1093) at org.apache.hadoop.ipc.Server$Handler.run(Server.java:1382) at org.apache.hadoop.ipc.Client.call(Client.java:1066) at org.apache.hadoop.ipc.RPC$Invoker.invoke(RPC.java:225) at $Proxy2.create(Unknown Source) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 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 $Proxy2.create(Unknown Source) at org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.<init>(DFSClient.java:3245) at org.apache.hadoop.hdfs.DFSClient.create(DFSClient.java:713) at org.apache.hadoop.hdfs.DistributedFileSystem.create(DistributedFileSystem.java:182) at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:555) at org.apache.hadoop.io.SequenceFile$RecordCompressWriter.<init>(SequenceFile.java:1132) at org.apache.hadoop.io.SequenceFile.createWriter(SequenceFile.java:397) at org.apache.hadoop.io.SequenceFile.createWriter(SequenceFile.java:354) at org.apache.hadoop.io.SequenceFile.createWriter(SequenceFile.java:476) at org.apache.hadoop.io.MapFile$Writer.<init>(MapFile.java:157) at org.apache.hadoop.io.MapFile$Writer.<init>(MapFile.java:134) at org.apache.hadoop.io.MapFile$Writer.<init>(MapFile.java:92) at org.apache.nutch.parse.ParseOutputFormat.getRecordWriter(ParseOutputFormat.java:110) at org.apache.hadoop.mapred.ReduceTask$OldTrackingRecordWriter.<init>(ReduceTask.java:448) at org.apache.hadoop.mapred.ReduceTask.runOldReducer(ReduceTask.java:490) at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:420) at org.apache.hadoop.mapred.Child$4.run(Child.java:255) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:396) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1093) at org.apache.hadoop.mapred.Child.main(Child.java:249) I asked the hdfs-user mailing list and i got the following answer: "Looks like you have reduce speculation turned on, but the ParseOutputFormat you're using doesn't properly name its output files distinctly based on the task attempt ID. As a workaround you can probably turn off speculative execution for reduces, but you should also probably file a Nutch bug." -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira