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https://issues.apache.org/jira/browse/HADOOP-751?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sameer Paranjpye resolved HADOOP-751.
-------------------------------------
Resolution: Invalid
Investigation revealed that the Namenode CPU usage was caused by lack of heap
space. Reducing memory consumption in the Namenode is partially addressed by
HADOOP-803. More improvements will follow.
> Namenode constantly using up 100% CPU
> -------------------------------------
>
> Key: HADOOP-751
> URL: https://issues.apache.org/jira/browse/HADOOP-751
> Project: Hadoop
> Issue Type: Bug
> Components: dfs
> Affects Versions: 0.8.0
> Reporter: Koji Noguchi
> Assigned To: Sameer Paranjpye
>
> Trying to figure out the exact cause, but CPU load of the namenode is
> constantly 100% without any file exchanges.
> .log file of the namenode showing the following exception about every 20
> seconds.
> 2006-11-27 16:02:07,199 INFO org.apache.hadoop.ipc.Server: IPC Server handler
> 5 on 8020 call error: java.io.IOException: java.util.NoSuchElementException
> java.io.IOException: java.util.NoSuchElementException
> at java.util.TreeMap$PrivateEntryIterator.nextEntry(TreeMap.java:1029)
> at java.util.TreeMap$KeyIterator.next(TreeMap.java:1058)
> at java.util.AbstractCollection.toArray(AbstractCollection.java:176)
> at
> org.apache.hadoop.dfs.DatanodeDescriptor.getBlocks(DatanodeDescriptor.java:96)
> at org.apache.hadoop.dfs.FSNamesystem.processReport(FSNamesystem.java:1446)
> at org.apache.hadoop.dfs.NameNode.blockReport(NameNode.java:506)
> at sun.reflect.GeneratedMethodAccessor11.invoke(Unknown Source)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:585)
> at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:387)
> at org.apache.hadoop.ipc.Server$Handler.run(Server.java:518)
> On some of the datanodes, .log file is showing
> 2006-11-27 16:03:57,542 WARN org.apache.hadoop.dfs.DataNode:
> org.apache.hadoop.ipc.RemoteException: java.io.IOException:
> java.util.NoSuchElementException
> at java.util.TreeMap$PrivateEntryIterator.nextEntry(TreeMap.java:1029)
> at java.util.TreeMap$KeyIterator.next(TreeMap.java:1058)
> at java.util.AbstractCollection.toArray(AbstractCollection.java:176)
> at
> org.apache.hadoop.dfs.DatanodeDescriptor.getBlocks(DatanodeDescriptor.java:96)
> at org.apache.hadoop.dfs.FSNamesystem.processReport(FSNamesystem.java:1446)
> at org.apache.hadoop.dfs.NameNode.blockReport(NameNode.java:506)
> at sun.reflect.GeneratedMethodAccessor11.invoke(Unknown Source)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:585)
> at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:387)
> at org.apache.hadoop.ipc.Server$Handler.run(Server.java:518)
> at org.apache.hadoop.ipc.Client$Connection.run(Client.java:248)
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