I'm running three Cassandra nodes in virtual machines.

During a 'get' operation from Cassandra-remote directed at one of these nodes, I'm receiving the following output

vadmin@vadmin:~/cassandra$ interface/gen-py/cassandra/Cassandra-remote -h 192.168.133.130:9160 get 'MockElementLibrary' '0401318uuuuruepwdcznr' "ColumnPath('strings', None, 'id')" 2
/usr/local/lib/python2.6/dist-packages/thrift/Thrift.py:58: DeprecationWarning: BaseException.message has been deprecated as of Python 2.6
  self.message = message
/usr/local/lib/python2.6/dist-packages/thrift/Thrift.py:99: DeprecationWarning: BaseException.message has been deprecated as of Python 2.6
  self.message = iprot.readString();
Traceback (most recent call last):
  File "interface/gen-py/cassandra/Cassandra-remote", line 93, in <module>
    pp.pprint(client.get(args[0],args[1],eval(args[2]),eval(args[3]),))
  File "/home/vadmin/cassandra-0.4.0-beta1/interface/gen-py/cassandra/Cassandra.py", line 182, in get
    return self.recv_get()
  File "/home/vadmin/cassandra-0.4.0-beta1/interface/gen-py/cassandra/Cassandra.py", line 201, in recv_get
    raise x
thrift.Thrift.TApplicationException/usr/local/lib/python2.6/dist-packages/thrift/Thrift.py:76: DeprecationWarning: BaseException.message has been deprecated as of Python 2.6
  if self.message:
/usr/local/lib/python2.6/dist-packages/thrift/Thrift.py:77: DeprecationWarning: BaseException.message has been deprecated as of Python 2.6
  return self.message
: Internal error processing get


The same 'get' operation from Cassandra-remote directed at another of these nodes, yields 'normal' output

vadmin@vadmin:~/cassandra$ interface/gen-py/cassandra/Cassandra-remote -h 192.168.133.129:9160 get 'MockElementLibrary' '0401318uuuuruepwdcznr' "ColumnPath('strings', None, 'id')" 2
Traceback (most recent call last):
  File "interface/gen-py/cassandra/Cassandra-remote", line 93, in <module>
    pp.pprint(client.get(args[0],args[1],eval(args[2]),eval(args[3]),))
  File "/home/vadmin/cassandra-0.4.0-beta1/interface/gen-py/cassandra/Cassandra.py", line 182, in get
    return self.recv_get()
  File "/home/vadmin/cassandra-0.4.0-beta1/interface/gen-py/cassandra/Cassandra.py", line 210, in recv_get
    raise result.nfe
ttypes.NotFoundException: NotFoundException()

Furthermore, querying the same column for (some) other keys is successful when no matter which node it is directed at.
Looking at the log for the node that produced the error from the query above:

DEBUG [pool-1-thread-22] 2009-08-19 16:54:57,618 CassandraServer.java (line 221) get
DEBUG [pool-1-thread-22] 2009-08-19 16:54:57,618 StorageProxy.java (line 420) strongread reading data for SliceByNamesReadCommand(table='MockElementLibrary', key='0401318uuuuruepwdcznr', columnParent='QueryPath(columnFamilyName='strings', superColumnName='null', columnName='null')', columns=[id,]) from 38184@null
DEBUG [pool-1-thread-22] 2009-08-19 16:54:57,619 StorageProxy.java (line 427) strongread reading digest for SliceByNamesReadCommand(table='MockElementLibrary', key='0401318uuuuruepwdcznr', columnParent='QueryPath(columnFamilyName='strings', superColumnName='null', columnName='null')', columns=[id,]) from 38185@192.168.133.129:7000
 WARN [MESSAGE-SERIALIZER-POOL:4] 2009-08-19 16:54:57,619 MessageSerializationTask.java (line 81) Exception was generated at : 08/19/2009 16:54:57 on thread MESSAGE-SERIALIZER-POOL:4

java.lang.NullPointerException
        at org.apache.cassandra.net.TcpConnection.<init>(TcpConnection.java:83)
        at org.apache.cassandra.net.TcpConnectionManager.getConnection(TcpConnectionManager.java:64)
        at org.apache.cassandra.net.MessagingService.getConnection(MessagingService.java:306)
        at org.apache.cassandra.net.MessageSerializationTask.run(MessageSerializationTask.java:66)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
        at java.lang.Thread.run(Thread.java:619)

DEBUG [RESPONSE-STAGE:4] 2009-08-19 16:54:57,622 ResponseVerbHandler.java (line 38) Processing response on a callback from 65B1E352-A0A3-1A7F-138B-9BEA3E1D787F@192.168.133.129:7000
ERROR [pool-1-thread-22] 2009-08-19 16:55:02,619 Cassandra.java (line 608) Internal error processing get
java.lang.RuntimeException: java.util.concurrent.TimeoutException: Operation timed out - received only 1 responses from 192.168.133.129:7000 .
        at org.apache.cassandra.service.CassandraServer.readColumnFamily(CassandraServer.java:100)
        at org.apache.cassandra.service.CassandraServer.get(CassandraServer.java:226)
        at org.apache.cassandra.service.Cassandra$Processor$get.process(Cassandra.java:602)
        at org.apache.cassandra.service.Cassandra$Processor.process(Cassandra.java:560)
        at org.apache.thrift.server.TThreadPoolServer$WorkerProcess.run(TThreadPoolServer.java:252)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
        at java.lang.Thread.run(Thread.java:619)
Caused by: java.util.concurrent.TimeoutException: Operation timed out - received only 1 responses from 192.168.133.129:7000 .
        at org.apache.cassandra.service.QuorumResponseHandler.get(QuorumResponseHandler.java:86)
        at org.apache.cassandra.service.StorageProxy.strongRead(StorageProxy.java:435)
        at org.apache.cassandra.service.StorageProxy.readProtocol(StorageProxy.java:330)
        at org.apache.cassandra.service.CassandraServer.readColumnFamily(CassandraServer.java:92)
        ... 7 more


It appears to me that there is a timeout during the QuorumResponseHandler processing, stemming from a NullPointerException that occurs as part of the read process. I suspect that this NullPointerException has something to do with the second DEBUG [pool-1-thread-22] comment regarding strongread ... from 38184@null.

Does anyone know why this might be happening?

Thanks for any insight,
Phil